• By Julien Barbier

Read or watch:

• Arguments to main
• argc and argv
• What does argc and argv mean?
• how to compile with unused variables

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

• How to use arguments passed to your program
• What are two prototypes of main that you know of, and in which case do you use one or the other
• How to use __attribute__((unused)) or (void) to compile functions with unused variables or parameters

• Allowed editors: vi, vim, emacs
• All your files will be compiled on Ubuntu 20.04 LTS using gcc, using the options -Wall -Werror -Wextra -pedantic -std=gnu89
• All your files should end with a new line
• A README.md file, at the root of the folder of the project is mandatory
• Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
• You are not allowed to use global variables
• No more than 5 functions per file
• The prototypes of all your functions and the prototype of the function _putchar should be included in your header file called main.h
• Don't forget to push your header file
• You are allowed to use the standard library

mandatory

Write a program that prints its name, followed by a new line.

• If you rename the program, it will print the new name, without having to compile it again
• You should not remove the path before the name of the program

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 0-whatsmyname.c -o mynameis
julien@ubuntu:~/0x0A. argc, argv$ ./mynameis
./mynameis
julien@ubuntu:~/0x0A. argc, argv$ mv mynameis mynewnameis
julien@ubuntu:~/0x0A. argc, argv$ ./mynewnameis
./mynewnameis
julien@ubuntu:~/0x0A. argc, argv$

Repo:

• GitHub repository: alx-low_level_programming
• Directory: 0x0A-argc_argv
• File: 0-whatsmyname.c

 Done? Help Check your code Get a sandbox

mandatory

Write a program that prints the number of arguments passed into it.

• Your program should print a number, followed by a new line

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 1-args.c -o nargs
julien@ubuntu:~/0x0A. argc, argv$ ./nargs
0
julien@ubuntu:~/0x0A. argc, argv$ ./nargs hello
1
julien@ubuntu:~/0x0A. argc, argv$ ./nargs "hello, world"
1
julien@ubuntu:~/0x0A. argc, argv$ ./nargs hello, world
2
julien@ubuntu:~/0x0A. argc, argv$

Repo:

• GitHub repository: alx-low_level_programming
• Directory: 0x0A-argc_argv
• File: 1-args.c

 Done? Help Check your code Get a sandbox

mandatory

Write a program that prints all arguments it receives.

• All arguments should be printed, including the first one
• Only print one argument per line, ending with a new line

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 2-args.c -o args
julien@ubuntu:~/0x0A. argc, argv$ ./args
./args
julien@ubuntu:~/0x0A. argc, argv$ ./args You can do anything, but not everything.
./args
You
can
do
anything,
but
not
everything.
julien@ubuntu:~/0x0A. argc, argv$

Repo:

• GitHub repository: alx-low_level_programming
• Directory: 0x0A-argc_argv
• File: 2-args.c

 Done? Help Check your code Get a sandbox

mandatory

Write a program that multiplies two numbers.

• Your program should print the result of the multiplication, followed by a new line
• You can assume that the two numbers and result of the multiplication can be stored in an integer
• If the program does not receive two arguments, your program should print Error, followed by a new line, and return 1

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 3-mul.c -o mul
julien@ubuntu:~/0x0A. argc, argv$ ./mul 2 3
6
julien@ubuntu:~/0x0A. argc, argv$ ./mul 2 -3
-6
julien@ubuntu:~/0x0A. argc, argv$ ./mul 2 0
0
julien@ubuntu:~/0x0A. argc, argv$ ./mul 245 3245342
795108790
julien@ubuntu:~/0x0A. argc, argv$ ./mul
Error
julien@ubuntu:~/0x0A. argc, argv$

Repo:

• GitHub repository: alx-low_level_programming
• Directory: 0x0A-argc_argv
• File: 3-mul.c

 Done? Help Check your code Get a sandbox

mandatory

Write a program that adds positive numbers.

• Print the result, followed by a new line
• If no number is passed to the program, print 0, followed by a new line
• If one of the number contains symbols that are not digits, print Error, followed by a new line, and return 1
• You can assume that numbers and the addition of all the numbers can be stored in an int

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 4-add.c -o add
julien@ubuntu:~/0x0A. argc, argv$ ./add 1 1
2
julien@ubuntu:~/0x0A. argc, argv$ ./add 1 10 100 1000
1111
julien@ubuntu:~/0x0A. argc, argv$ ./add 1 2 3 e 4 5
Error
julien@ubuntu:~/0x0A. argc, argv$ ./add
0
julien@ubuntu:~/0x0A. argc, argv$

Repo:

• GitHub repository: alx-low_level_programming
• Directory: 0x0A-argc_argv
• File: 4-add.c

#advanced

Score: 0.00% (Checks completed: 0.00%)

Write a program that prints the minimum number of coins to make change for an amount of money.

• Usage: ./change cents
• where cents is the amount of cents you need to give back
• if the number of arguments passed to your program is not exactly 1, print Error, followed by a new line, and return 1
• you should use atoi to parse the parameter passed to your program
• If the number passed as the argument is negative, print 0, followed by a new line
• You can use an unlimited number of coins of values 25, 10, 5, 2, and 1 cent

julien@ubuntu:~/0x0A. argc, argv$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 100-change.c -o change
julien@ubuntu:~/0x0A. argc, argv$ ./change
Error
julien@ubuntu:~/0x0A. argc, argv$ ./change 10
1
julien@ubuntu:~/0x0A. argc, argv$ ./change 100
4
julien@ubuntu:~/0x0A. argc, argv$ ./change 101
5
julien@ubuntu:~/0x0A. argc, argv$ ./change 13
3
julien@ubuntu:~/0x0A. argc, argv$

Repo:

• GitHub repository: alx-low_level_programming
• Directory: 0x0A-argc_argv
• File: 100-change.c