## Copyright Mantu Matei 312CA 2022-2023
# README tema02: My Octave

## Description
This program written in C implements some of the matrix functions featured in 
GNU Octave.

## What does it do?
Firstly, it creates a dynamic array of matrices that will be used to save the 
matrices received as input or created as result of a function. Two dynamic 
arrays are also used in order to store the size of each matrix.
A character is then read, signifying what operation will be executed:
1. `L` - Load a matrix scanned from STDIN, together with its number of lines 
and columns. The program doubles the allocated memory the array of matrices 
every time it runs out.

2. `D` - Followed by a number `i`, prints the size of the matrix on the `i`-th 
position.

3. `P` - Followed by a number `i`, prints the `i`-th matrix.

4. `C` - Followed by `i`, crops the `i`-th matrix. It is implemented by 
creating a copy of the matrix. The new number of columns and lines is read, 
together with the indices of the columns and lines kept. The original matrix 
is then overwritten with the requested values and then resized.

5. `M` - Followed by two numbers `i` and `j`, multiply the two matrices using
the naive approach and saves the result at the end of the matrix array.

6. `O` - sorts the matrix array by sum of the each matrix' elements. Uses 
bubble sort because it's a stable sorting algorithm that is easy to write.

7. `T` - Followed by `i`, transposes the `i`-th matrix. Done by increasing
the matrix' size, transposing the elements and then shrinking the matrix
to the new size. (Unless it's a square matrix.)

8. `R` - Followed by `i` and `pow`, raises the `i`-th matrix to the `pow`-th
power using an algorithm similar to Fast Exponentiation Algorithm for numbers.

9. `F` - Followed by `i`, deletes the `i`-th matrix from the matrix array. All
matrices to the right are then shifted by one position to the left, done by 
swapping the pointers. (In order to leave no gap in the array.) The program 
then checks whether it could safely half the memory used for the matrix array.

10. `Q` - Frees all memory used by the program and then exits the program.

11. `S` - BONUS - Matrix Product using the Strassen Algorithm. Works only
for square matrices with a size of `2^n`, `n` being a natural number. 

If the char scanned isn't `Q`, another char is scanned. If the char is 
not in the list above, an error message is printed. If an int is scanned, 
it is ignored.