diff --git a/doc/specs/stdlib_io.md b/doc/specs/stdlib_io.md
index 40cb2b426..0fa0d30b6 100644
--- a/doc/specs/stdlib_io.md
+++ b/doc/specs/stdlib_io.md
@@ -131,3 +131,130 @@ program demo_savetxt
     call savetxt('example.dat', x) 
 end program demo_savetxt
 ```
+
+## `disp` - display your data
+
+### Status
+
+Experimental
+
+### Class
+
+Impure subroutine.
+
+### Description
+
+Outputs a `logical/integer/real/complex/character/string_type` scalar or `logical/integer/real/complex` and rank-1/rank-2 array to the screen or a file `unit`.
+
+#### More details
+
+```fortran
+call disp( A(i, j, 2, :, 1:10) [, header, unit, brief] )    !! `i, j, ...` can be determined by `do` loop.
+```
+
+For `complex` type, the output format is `*(A25, 1X)`; 
+For    other types, the output format is `*(A12, 1X)`.
+
+To prevent users from accidentally passing large-length arrays to `disp`, causing unnecessary io blockage:
+1. If the `brief` argument is not specified, `disp` will print **the brief array content with a length of `10*50` by default**.
+2. Specify `brief=.true.`, `disp` will print **the brief array content with a length of `5*5`**;
+3. Specify `brief=.false.`, `disp` will print **`all` the contents of the array**.
+
+### Syntax
+
+`call [[stdlib_io(module):disp(interface)]]([x, header, unit, brief])`  
+
+### Arguments
+
+`x`: Shall be a `logical/integer/real/complex/string_type` scalar or `logical/integer/real/complex` and rank-1/rank-2 array.
+This argument is `intent(in)` and `optional`.
+
+`header`: Shall be a `character(len=*)` scalar. 
+This argument is `intent(in)` and `optional`.
+
+`unit`: Shall be an `integer` scalar linked to an IO stream.
+This argument is `intent(in)` and `optional`.
+
+`brief`: Shall be a `logical` scalar.
+This argument is `intent(in)` and `optional`.  
+Controls an abridged version of the `x` object is printed.
+
+### Output
+
+The result is to print `header` and `x` on the screen (or another output `unit/file`) in this order.  
+If `x` is a rank-1/rank-2 `array` type, the dimension length information of the `array` will also be outputted.
+
+If `disp` is not passed any arguments, a blank line is printed.
+
+If the `x` is present and of `real/complex` type, the data will retain four significant decimal places, like `(g0.4)`.
+
+### Example
+
+```fortran
+program test_io_disp
+    
+    use stdlib_io, only: disp
+
+    real(8) :: r(2, 3)
+    complex :: c(2, 3), c_3d(2, 100, 20)
+    integer :: i(2, 3)
+    logical :: l(10, 10)
+    r = 1.; c = 1.; c_3d = 2.; i = 1; l = .true.
+    r(1, 1) = -1.e-11
+    r(1, 2) = -1.e10
+    c(2, 2) = (-1.e10,-1.e10)
+    c_3d(1,3,1) = (1000, 0.001)
+    c_3d(1,3,2) = (1.e4, 100.)
+    call disp('string', header='disp(string):')
+    call disp('It is a note.')
+    call disp()
+    call disp(r, header='disp(r):')
+    call disp(r(1,:), header='disp(r(1,:))')
+    call disp(c, header='disp(c):')
+    call disp(i, header='disp(i):')
+    call disp(l, header='disp(l):', brief=.true.)
+    call disp(c_3d(:,:,3), header='disp(c_3d(:,:,3)):', brief=.true.)
+    call disp(c_3d(2,:,:), header='disp(c_3d(2,:,:)):', brief=.true.)
+
+end program test_io_disp
+```
+**Results:**
+```fortran
+ disp(string):
+ string
+ It is a note.
+
+ disp(r):
+ [matrix size: 2×3]
+ -0.1000E-10  -0.1000E+11    1.000
+   1.000        1.000        1.000
+ disp(r(1,:))
+ [vector size: 3]
+ -0.1000E-10  -0.1000E+11    1.000
+ disp(c):
+ [matrix size: 2×3]
+            (1.000,0.000)             (1.000,0.000)             (1.000,0.000)
+            (1.000,0.000) (-0.1000E+11,-0.1000E+11)             (1.000,0.000)
+ disp(i):
+ [matrix size: 2×3]
+           1            1            1
+           1            1            1
+ disp(l):
+ [matrix size: 10×10]
+           T            T            T          ...            T
+           T            T            T          ...            T
+           T            T            T          ...            T
+           :            :            :            :            :
+           T            T            T          ...            T
+ disp(c_3d(:,:,3)):
+ [matrix size: 2×100]
+            (2.000,0.000)             (2.000,0.000)             (2.000,0.000)                       ...             (2.000,0.000)  
+            (2.000,0.000)             (2.000,0.000)             (2.000,0.000)                       ...             (2.000,0.000)  
+ disp(c_3d(2,:,:)):
+ [matrix size: 100×20]
+            (2.000,0.000)             (2.000,0.000)             (2.000,0.000)                       ...             (2.000,0.000)  
+            (2.000,0.000)             (2.000,0.000)             (2.000,0.000)                       ...             (2.000,0.000)  
+            (2.000,0.000)             (2.000,0.000)             (2.000,0.000)                       ...             (2.000,0.000)  
+                        :                         :                         :                         :                         :  
+            (2.000,0.000)             (2.000,0.000)             (2.000,0.000)                       ...             (2.000,0.000) 
+```
\ No newline at end of file
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b56d75b0e..08eb00dac 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -7,6 +7,7 @@ set(fppFiles
     stdlib_bitsets_64.fypp
     stdlib_bitsets_large.fypp
     stdlib_io.fypp
+    stdlib_io_disp.fypp
     stdlib_linalg.fypp
     stdlib_linalg_diag.fypp
     stdlib_linalg_outer_product.fypp
diff --git a/src/Makefile.manual b/src/Makefile.manual
index 7576cf3d8..2ee03fc57 100644
--- a/src/Makefile.manual
+++ b/src/Makefile.manual
@@ -4,6 +4,7 @@ SRCFYPP = \
         stdlib_bitsets_large.fypp \
         stdlib_bitsets.fypp \
         stdlib_io.fypp \
+        stdlib_io_disp.fypp \
         stdlib_linalg.fypp \
         stdlib_linalg_diag.fypp \
         stdlib_linalg_outer_product.fypp \
@@ -27,8 +28,8 @@ SRCFYPP = \
         stdlib_stats_moment_scalar.fypp \
         stdlib_stats_var.fypp \
         stdlib_math.fypp \
-	stdlib_math_linspace.fypp \
-	stdlib_math_logspace.fypp \
+        stdlib_math_linspace.fypp \
+        stdlib_math_logspace.fypp \
         stdlib_stats_distribution_PRNG.fypp \
         stdlib_string_type.fypp \
         stdlib_string_type_constructor.fypp \
@@ -85,7 +86,12 @@ stdlib_io.o: \
     stdlib_error.o \
     stdlib_optval.o \
     stdlib_kinds.o \
-    stdlib_ascii.o
+    stdlib_ascii.o \
+    stdlib_string_type.o
+stdlib_io_disp.o: \
+    stdlib_strings.o \
+    stdlib_string_type.o \
+    stdlib_io.o
 stdlib_linalg.o: \
     stdlib_kinds.o
 stdlib_linalg_diag.o: \
diff --git a/src/stdlib_io.fypp b/src/stdlib_io.fypp
index dcacaa644..4e56f00a9 100644
--- a/src/stdlib_io.fypp
+++ b/src/stdlib_io.fypp
@@ -7,18 +7,52 @@ module stdlib_io
   !! ([Specification](../page/specs/stdlib_io.html))
 
   use stdlib_kinds, only: sp, dp, qp, &
-      int8, int16, int32, int64
+      int8, int16, int32, int64, lk, c_bool
   use stdlib_error, only: error_stop
   use stdlib_optval, only: optval
   use stdlib_ascii, only: is_blank
+  use stdlib_string_type, only: string_type
   implicit none
   private
   ! Public API
-  public :: loadtxt, savetxt, open
+  public :: loadtxt, savetxt, open, disp
 
   ! Private API that is exposed so that we can test it in tests
   public :: parse_mode
 
+
+  !> version: experimental
+  !>
+  !> Display a scalar, vector or matrix.
+  !> ([Specification](../page/specs/stdlib_io.html#disp-display-your-data-to-the-screen-or-another-output-unit))
+  interface disp
+    #:set DISP_KINDS_TYPES = REAL_KINDS_TYPES + INT_KINDS_TYPES &
+        & + CMPLX_KINDS_TYPES + LOG_KINDS_TYPES
+    #:set DISP_RANKS = range(0, 3)
+    #:for k1, t1 in DISP_KINDS_TYPES
+    #:for rank in DISP_RANKS
+    module subroutine disp_${rank}$_${t1[0]}$${k1}$(x, header, unit, brief)
+        ${t1}$, intent(in) :: x${ranksuffix(rank)}$
+        character(len=*), intent(in), optional :: header
+        integer,          intent(in), optional :: unit
+        logical,          intent(in), optional :: brief
+    end subroutine disp_${rank}$_${t1[0]}$${k1}$
+    #:endfor
+    #:endfor
+    module subroutine disp_character(x, header, unit, brief)
+        character(len=*), intent(in), optional :: x
+        character(len=*), intent(in), optional :: header
+        integer,          intent(in), optional :: unit
+        logical,          intent(in), optional :: brief
+    end subroutine disp_character
+    module subroutine disp_string_type(x, header, unit, brief)
+        type(string_type), intent(in)           :: x
+        character(len=*),  intent(in), optional :: header
+        integer,           intent(in), optional :: unit
+        logical,           intent(in), optional :: brief
+    end subroutine disp_string_type
+  end interface disp
+
   interface loadtxt
     !! version: experimental
     !!
diff --git a/src/stdlib_io_disp.fypp b/src/stdlib_io_disp.fypp
new file mode 100644
index 000000000..5dee5337c
--- /dev/null
+++ b/src/stdlib_io_disp.fypp
@@ -0,0 +1,213 @@
+#:include "common.fypp"
+#:set RIL_KINDS_TYPES = REAL_KINDS_TYPES + INT_KINDS_TYPES + LOG_KINDS_TYPES
+
+submodule (stdlib_io) stdlib_io_disp
+
+    use, intrinsic :: iso_fortran_env, only: output_unit
+    use stdlib_strings,     only: to_string
+    use stdlib_string_type, only: char
+    implicit none
+    
+    character(len=*), parameter :: rfmt        = '(*(g12.4, 1x))'
+    character(len=*), parameter :: cfmt        = '(*(g25.0, 1x))'
+    character(len=*), parameter :: fmt_        = 'g0.4'
+    integer,          parameter :: brief_col   = 5
+    integer,          parameter :: brief_row   = 5
+    integer,          parameter :: default_col = 10
+    integer,          parameter :: default_row = 50
+    
+contains
+    
+    #:for k1, t1 in RIL_KINDS_TYPES
+    #! Display a/an ${t1}$ scalar.
+    module procedure disp_0_${t1[0]}$${k1}$
+        integer :: unit_
+
+        unit_ = optval(unit, output_unit)
+
+        if (present(header)) write(unit_, *) header
+        write(unit_, rfmt) x
+
+    end procedure disp_0_${t1[0]}$${k1}$
+
+    #! Display a/an ${t1}$ vector.
+    module procedure disp_1_${t1[0]}$${k1}$
+        integer :: unit_
+        logical :: brief_
+        integer :: m, col
+        
+        unit_  = optval(unit, output_unit)
+        brief_ = optval(brief, .true.)
+        col    = merge(brief_col, default_col, present(brief) .and. brief_)
+        m      = size(x, 1)
+
+        if (present(header)) write(unit_, *) header
+        write(unit_, *) '[vector size: ' // to_string(m) // ']'
+
+        if (brief_ .and. m > col) then
+            #! Brief Print.
+            write(unit_, rfmt) x(1:col-2), '...', x(m)
+        else
+            #! Full Print.
+            write(unit_, rfmt) x(:)
+        end if
+
+    end procedure disp_1_${t1[0]}$${k1}$
+
+    #! Display a/an ${t1}$ matrix.
+    module procedure disp_2_${t1[0]}$${k1}$
+        integer :: unit_
+        logical :: brief_
+        integer :: i, m, n
+        integer :: col, row
+        character(len=1) :: colon(default_col)
+
+        unit_  = optval(unit, output_unit)
+        brief_ = optval(brief, .true.)
+        col    = merge(brief_col, default_col, present(brief) .and. brief_)
+        row    = merge(brief_row, default_row, present(brief) .and. brief_)
+        m      = size(x, 1)
+        n      = size(x, 2)
+
+        if (present(header)) write(unit_, *) header
+        write(unit_, *) '[matrix size: ' // to_string(m) // '×' // to_string(n) // ']'
+
+        if (brief_ .and. (m > col .or. n > row)) then
+            #! Brief Print.
+            colon = ':'
+            if (m > col .and. n > row) then
+                do i = 1, row-2
+                    write(unit_, rfmt) x(i,1:col-2), '...', x(i,n)
+                end do
+                write(unit_, rfmt) colon(1:col)
+                write(unit_, rfmt) x(m,1:col-2), '...', x(m,n)
+            elseif (m > col .and. n <= row) then
+                do i = 1, 3
+                    write(unit_, rfmt) x(i,:)
+                end do
+                write(unit_, rfmt) colon(1:n)
+                write(unit_, rfmt) x(m,:)
+            elseif (m <= col .and. n > row) then
+                do i = 1, m
+                    write(unit_, rfmt) x(i,1:col-2), '...', x(i,n)
+                end do
+            end if
+        else
+            #! Full Print.
+            do i = 1, m
+                write(unit_, rfmt) x(i,:)
+            end do
+        end if
+
+    end procedure disp_2_${t1[0]}$${k1}$
+    #:endfor
+
+    #:for k1, t1 in CMPLX_KINDS_TYPES
+    #! Display a ${t1}$ scalar.
+    module procedure disp_0_${t1[0]}$${k1}$
+        integer :: unit_
+
+        unit_  = optval(unit, output_unit)
+
+        if (present(header)) write(unit_, *) header
+        write(unit_, cfmt) to_string(x, fmt_)
+
+    end procedure disp_0_${t1[0]}$${k1}$
+
+    #! Display a ${t1}$ vector.
+    module procedure disp_1_${t1[0]}$${k1}$
+        integer :: unit_
+        logical :: brief_
+        integer :: i, m, col
+
+        unit_  = optval(unit, output_unit)
+        brief_ = optval(brief, .true.)
+        col    = merge(brief_col, default_col, present(brief) .and. brief_)
+        m      = size(x, 1)
+
+        if (present(header)) write(unit_, *) header
+        write(unit_, *) '[vector size: ' // to_string(m) // ']'
+
+        if (brief_ .and. m > col) then
+            #! Brief Print.
+            write(unit_, cfmt) (to_string(x(i), fmt_), i=1, col-2), '...', to_string(x(m), fmt_)
+        else
+            #! Full Print.
+            write(unit_, cfmt) (to_string(x(i), fmt_), i=1, m)
+        end if
+
+    end procedure disp_1_${t1[0]}$${k1}$
+
+    #! Display a ${t1}$ matrix.
+    module procedure disp_2_${t1[0]}$${k1}$
+        integer :: unit_
+        logical :: brief_
+        integer :: i, j, m, n
+        integer :: col, row
+        character(len=1) :: colon(default_col)
+
+        unit_  = optval(unit, output_unit)
+        brief_ = optval(brief, .true.)
+        col    = merge(brief_col, default_col, present(brief) .and. brief_)
+        row    = merge(brief_row, default_row, present(brief) .and. brief_)
+        m      = size(x, 1)
+        n      = size(x, 2)
+
+        if (present(header)) write(unit_, *) header
+        write(unit_, *) '[matrix size: ' // to_string(m) // '×' // to_string(n) // ']'
+
+        if (brief_ .and. (m > col .or. n > row)) then
+            #! Brief Print.
+            colon = ':'
+            if (m > col .and. n > row) then
+                do i = 1, col-2
+                    write(unit_, cfmt) (to_string(x(i,j), fmt_), j=1, col-2), '...', to_string(x(i,n), fmt_)
+                end do
+                write(unit_, cfmt) colon(1:col)
+                write(unit_, cfmt) (to_string(x(m,j), fmt_), j=1, col-2), '...', to_string(x(m,n), fmt_)
+            elseif (m > col .and. n <= row) then
+                do i = 1, col-2
+                    write(unit_, cfmt) (to_string(x(i,j), fmt_), j=1, n)
+                end do
+                write(unit_, cfmt) colon(1:n)
+                write(unit_, cfmt) (to_string(x(m,j), fmt_), j=1, n)
+            elseif (m <= col .and. n > row) then
+                do i = 1, m
+                    write(unit_, cfmt) (to_string(x(m,j), fmt_), j=1, col-2), '...', to_string(x(m,n), fmt_)
+                end do
+            end if
+        else
+            #! Full Print.
+            do i = 1, m
+                write(unit_, cfmt) (to_string(x(i,j), fmt_), j=1, n)
+            end do
+        end if
+
+    end procedure disp_2_${t1[0]}$${k1}$
+    #:endfor
+
+    #! Display a `character` scalar.
+    module procedure disp_character
+        character(len=:), allocatable :: x_
+        integer :: unit_
+
+        x_ = optval(x, '')
+        unit_  = optval(unit, output_unit)
+
+        if (present(header)) write(unit_, *) header
+        write(unit_, *) x_
+
+    end procedure disp_character
+
+    #! Display a `string_type` scalar
+    module procedure disp_string_type
+        integer :: unit_
+
+        unit_ = optval(unit, output_unit)
+
+        if (present(header)) write(unit_, *) header
+        write(unit_, *) char(x)
+
+    end procedure disp_string_type
+
+end submodule stdlib_io_disp
\ No newline at end of file
diff --git a/src/tests/io/CMakeLists.txt b/src/tests/io/CMakeLists.txt
index 68388a5e5..8963859e5 100644
--- a/src/tests/io/CMakeLists.txt
+++ b/src/tests/io/CMakeLists.txt
@@ -8,3 +8,4 @@ set_tests_properties(savetxt_qp PROPERTIES LABELS quadruple_precision)
 
 ADDTEST(open)
 ADDTEST(parse_mode)
+ADDTEST(disp)
diff --git a/src/tests/io/Makefile.manual b/src/tests/io/Makefile.manual
index 3bbce9db7..cb7122ff1 100644
--- a/src/tests/io/Makefile.manual
+++ b/src/tests/io/Makefile.manual
@@ -3,7 +3,8 @@ PROGS_SRC = test_loadtxt.f90 \
 			test_loadtxt_qp.f90 \
 			test_savetxt_qp.f90 \
 			test_parse_mode.f90 \
-			test_open.f90
+			test_open.f90 \
+			test_disp.f90
 
 CLEAN_FILES = tmp.dat tmp_qp.dat io_open.dat io_open.stream
 
diff --git a/src/tests/io/test_disp.f90 b/src/tests/io/test_disp.f90
new file mode 100644
index 000000000..dc3268fe1
--- /dev/null
+++ b/src/tests/io/test_disp.f90
@@ -0,0 +1,410 @@
+module test_io_disp
+
+    use stdlib_strings, only: starts_with
+    use stdlib_string_type, only: string_type, assignment(=)
+    use stdlib_error, only: check
+    use stdlib_io, only: disp
+    use stdlib_optval, only: optval
+    implicit none
+
+    integer :: unit
+    character(len=200) :: string
+
+contains
+
+    subroutine check_formatter(actual, expected, description, partial)
+        character(len=*), intent(in) :: actual, expected, description
+        logical, intent(in), optional :: partial
+        logical :: stat
+        character(len=:), allocatable :: msg
+
+        if (optval(partial, .false.)) then
+            stat = starts_with(actual, expected)
+        else
+            stat = actual == expected
+        end if
+
+        if (.not. stat) then
+            msg = description//new_line("a")// &
+                & "Expected: '"//expected//"' but got '"//actual//"'"
+        else
+            print '(" - ", a, /, "   Result: ''", a, "''")', description, actual
+        end if
+
+        call check(stat, msg)
+
+    end subroutine check_formatter
+
+    subroutine test_io_disp_complex
+        complex :: c(6,6) = (1.0, 1.0)
+
+        open(newunit=unit, status='scratch')
+        call disp(c(1,1), header='Test_io_disp_complex_scalar (brief) : ', brief=.true.)
+        call disp(c(1,1), unit=unit, header='Test_io_disp_complex_scalar (brief) : ', brief=.true.)
+
+        call disp(c(1,:), header='Test_io_disp_complex_vector (brief) : ', brief=.true.)
+        call disp(c(1,:), unit=unit, header='Test_io_disp_complex_vector (brief) : ', brief=.true.)
+
+        call disp(c(:,1), header='Test_io_disp_complex_vector : ', brief=.false.)
+        call disp(c(:,1), unit=unit, header='Test_io_disp_complex_vector : ', brief=.false.)
+
+        call disp(c(1:2,1:2), header='Test_io_disp_complex_matrix : ', brief=.false.)
+        call disp(c(1:2,1:2), unit=unit, header='Test_io_disp_complex_matrix : ', brief=.false.)
+
+        call disp(c(:,:), header='Test_io_disp_complex_matrix (brief) : ', brief=.true.)
+        call disp(c(:,:), unit=unit, header='Test_io_disp_complex_matrix (brief) : ', brief=.true.)
+    
+        !! Checks
+        rewind(unit)
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_complex_scalar (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '(1.000,1.000)', 'Value')
+        
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_complex_vector (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[vector size: 6]', 'Vector Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '(1.000,1.000)             (1.000,1.000)             (1.000,1.000)  &
+        &                     ...             (1.000,1.000)', 'Brief Vector')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_complex_vector :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[vector size: 6]', 'Vector Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '(1.000,1.000)             (1.000,1.000)             (1.000,1.000)    &
+        &         (1.000,1.000)             (1.000,1.000)             (1.000,1.000)', 'Brief Vector')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_complex_matrix :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[matrix size: 2×2]', 'Matrix Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '(1.000,1.000)             (1.000,1.000)', 'Matrix Vector 1')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '(1.000,1.000)             (1.000,1.000)', 'Matrix Vector 2')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_complex_matrix (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[matrix size: 6×6]', 'Matrix Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '(1.000,1.000)             (1.000,1.000)             (1.000,1.000)    &
+        &                   ...             (1.000,1.000)', 'Matrix Vector 1')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '(1.000,1.000)             (1.000,1.000)             (1.000,1.000)    &
+        &                   ...             (1.000,1.000)', 'Matrix Vector 2')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '(1.000,1.000)             (1.000,1.000)             (1.000,1.000)    &
+        &                   ...             (1.000,1.000)', 'Matrix Vector 3')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        ':                         :                         :                &
+        &         :                         :', 'Matrix Vector ..')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '(1.000,1.000)             (1.000,1.000)             (1.000,1.000)    &
+        &                   ...             (1.000,1.000)', 'Matrix Vector Size(Matrix, 1)')
+        close(unit)
+
+    end subroutine test_io_disp_complex
+
+    subroutine test_io_disp_real
+
+        real :: r(6,6) = 1.0
+        
+        open(newunit=unit, status='scratch')
+        call disp(r(1,1), header='Test_io_disp_real_scalar (brief) : ', brief=.true.)
+        call disp(r(1,1), unit=unit, header='Test_io_disp_real_scalar (brief) : ', brief=.true.)
+
+        call disp(r(1,:), header='Test_io_disp_real_vector (brief) : ', brief=.true.)
+        call disp(r(1,:), unit=unit, header='Test_io_disp_real_vector (brief) : ', brief=.true.)
+
+        call disp(r(:,1), header='Test_io_disp_real_vector : ', brief=.false.)
+        call disp(r(:,1), unit=unit, header='Test_io_disp_real_vector : ', brief=.false.)
+
+        call disp(r(1:2,1:2), header='Test_io_disp_real_matrix : ', brief=.false.)
+        call disp(r(1:2,1:2), unit=unit, header='Test_io_disp_real_matrix : ', brief=.false.)
+
+        call disp(r(:,:), header='Test_io_disp_real_matrix (brief) : ', brief=.true.)
+        call disp(r(:,:), unit=unit, header='Test_io_disp_real_matrix (brief) : ', brief=.true.)
+    
+        !! Checks
+        rewind(unit)
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_real_scalar (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '1.000', 'Value')
+        
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_real_vector (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[vector size: 6]', 'Vector Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1.000        1.000        1.000              ...    1.000', 'Brief Vector')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_real_vector :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[vector size: 6]', 'Vector Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1.000        1.000        1.000        1.000        1.000        1.000', 'Brief Vector')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_real_matrix :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[matrix size: 2×2]', 'Matrix Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1.000        1.000', 'Matrix Vector 1')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1.000        1.000', 'Matrix Vector 2')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_real_matrix (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[matrix size: 6×6]', 'Matrix Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1.000        1.000        1.000              ...    1.000', 'Matrix Vector 1')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1.000        1.000        1.000              ...    1.000', 'Matrix Vector 2')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1.000        1.000        1.000              ...    1.000', 'Matrix Vector 3')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        ':            :            :            :            :', 'Matrix Vector ..')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1.000        1.000        1.000              ...    1.000', 'Matrix Vector Size(Matrix, 1)')
+        close(unit)
+
+    end subroutine test_io_disp_real
+
+    subroutine test_io_disp_integer
+
+        integer :: i(6,6) = 1
+        
+        open(newunit=unit, status='scratch')
+        call disp(i(1,1), header='Test_io_disp_integer_scalar (brief) : ', brief=.true.)
+        call disp(i(1,1), unit=unit, header='Test_io_disp_integer_scalar (brief) : ', brief=.true.)
+
+        call disp(i(1,:), header='Test_io_disp_integer_vector (brief) : ', brief=.true.)
+        call disp(i(1,:), unit=unit, header='Test_io_disp_integer_vector (brief) : ', brief=.true.)
+
+        call disp(i(:,1), header='Test_io_disp_integer_vector : ', brief=.false.)
+        call disp(i(:,1), unit=unit, header='Test_io_disp_integer_vector : ', brief=.false.)
+
+        call disp(i(1:2,1:2), header='Test_io_disp_integer_matrix : ', brief=.false.)
+        call disp(i(1:2,1:2), unit=unit, header='Test_io_disp_integer_matrix : ', brief=.false.)
+
+        call disp(i(:,:), header='Test_io_disp_integer_matrix (brief) : ', brief=.true.)
+        call disp(i(:,:), unit=unit, header='Test_io_disp_integer_matrix (brief) : ', brief=.true.)
+    
+        !! Checks
+        rewind(unit)
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_integer_scalar (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '1', 'Value')
+        
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_integer_vector (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[vector size: 6]', 'Vector Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1            1            1          ...            1', 'Brief Vector')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_integer_vector :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[vector size: 6]', 'Vector Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1            1            1            1            1            1', 'Brief Vector')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_integer_matrix :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[matrix size: 2×2]', 'Matrix Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1            1', 'Matrix Vector 1')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1            1', 'Matrix Vector 2')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_integer_matrix (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[matrix size: 6×6]', 'Matrix Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1            1            1          ...            1', 'Matrix Vector 1')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1            1            1          ...            1', 'Matrix Vector 2')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1            1            1          ...            1', 'Matrix Vector 3')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        ':            :            :            :            :', 'Matrix Vector ..')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        '1            1            1          ...            1', 'Matrix Vector Size(Matrix, 1)')
+        close(unit)
+
+    end subroutine test_io_disp_integer
+
+    subroutine test_io_disp_logical
+
+        logical :: l(6,6) = .true.
+        ! unit = open(filenanme, 'w+t')
+        open(newunit=unit, status='scratch')
+        call disp(l(1,1), header='Test_io_disp_logical_scalar (brief) : ', brief=.true.)
+        call disp(l(1,1), unit=unit, header='Test_io_disp_logical_scalar (brief) : ', brief=.true.)
+
+        call disp(l(1,:), header='Test_io_disp_logical_vector (brief) : ', brief=.true.)
+        call disp(l(1,:), unit=unit, header='Test_io_disp_logical_vector (brief) : ', brief=.true.)
+
+        call disp(l(:,1), header='Test_io_disp_logical_vector : ', brief=.false.)
+        call disp(l(:,1), unit=unit, header='Test_io_disp_logical_vector : ', brief=.false.)
+
+        call disp(l(1:2,1:2), header='Test_io_disp_logical_matrix : ', brief=.false.)
+        call disp(l(1:2,1:2), unit=unit, header='Test_io_disp_logical_matrix : ', brief=.false.)
+
+        call disp(l(:,:), header='Test_io_disp_logical_matrix (brief) : ', brief=.true.)
+        call disp(l(:,:), unit=unit, header='Test_io_disp_logical_matrix (brief) : ', brief=.true.)
+    
+        !! Checks
+        rewind(unit)
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_logical_scalar (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'T', 'Value')
+        
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_logical_vector (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[vector size: 6]', 'Vector Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        'T            T            T          ...            T', 'Brief Vector')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_logical_vector :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[vector size: 6]', 'Vector Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        'T            T            T            T            T            T', 'Brief Vector')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_logical_matrix :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[matrix size: 2×2]', 'Matrix Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        'T            T', 'Matrix Vector 1')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        'T            T', 'Matrix Vector 2')
+
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_logical_matrix (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), '[matrix size: 6×6]', 'Matrix Info')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        'T            T            T          ...            T', 'Matrix Vector 1')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        'T            T            T          ...            T', 'Matrix Vector 2')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        'T            T            T          ...            T', 'Matrix Vector 3')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        ':            :            :            :            :', 'Matrix Vector ..')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), &
+        'T            T            T          ...            T', 'Matrix Vector Size(Matrix, 1)')
+        close(unit)
+
+    end subroutine test_io_disp_logical
+
+    subroutine test_io_disp_character
+
+        character(*), parameter :: str = 'It is a character.'
+        ! unit = open(filenanme, 'w+t')
+        open(newunit=unit, status='scratch')
+        call disp(str, header='Test_io_disp_character_scalar (brief) : ', brief=.true.)
+        call disp(str, unit=unit, header='Test_io_disp_character_scalar (brief) : ', brief=.true.)
+    
+        !! Checks
+        rewind(unit)
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_character_scalar (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'It is a character.', 'Value')
+        close(unit)
+
+    end subroutine test_io_disp_character
+
+    subroutine test_io_disp_string_type
+
+        type(string_type) :: str
+        
+        str = 'It is a string_type.'
+        open(newunit=unit, status='scratch')
+        call disp(str, header='Test_io_disp_string_type_scalar (brief) : ', brief=.true.)
+        call disp(str, unit=unit, header='Test_io_disp_string_type_scalar (brief) : ', brief=.true.)
+    
+        !! Checks
+        rewind(unit)
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'Test_io_disp_string_type_scalar (brief) :', 'Header')
+        read(unit, '(A200)') string
+        call check_formatter(trim(adjustl(string)), 'It is a string_type.', 'Value')
+        close(unit)
+
+    end subroutine test_io_disp_string_type
+
+end module test_io_disp
+
+program tester
+
+    use test_io_disp
+    ! real(4) :: x(51,51)
+
+    call test_io_disp_complex
+    call test_io_disp_real
+    call test_io_disp_integer
+    call test_io_disp_logical
+    call test_io_disp_character
+    call test_io_disp_string_type
+
+    !> Content that is difficult to test: The length of the dimension is too large
+    !>  to print and check by a test program.
+    ! x = 0.0
+    ! call disp(x, header="Test_io_disp_real_matrix (51×51)(default) : [10×50]")
+    ! call disp(x, header="Test_io_disp_real_matrix (51×51)(brief=.true.) : [5×5]", brief=.true.)
+    ! call disp(x, header="Test_io_disp_real_matrix (51×51)(brief=.false.) : [all]", brief=.false.)
+
+end program tester
\ No newline at end of file