- 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
Read or watch:
- Arguments to main.
- argc and argv.
- What does argc and argv mean?.
- how to compile with unused variables.
- 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 calledmain.h
- Don’t forget to push your header file
- You are allowed to use the standard library
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$
Solution: 0-whatsmyname.c.
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$
Solution: 1-args.c.
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$
Solution: 2-args.c.
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 return1
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$
Solution: 3-mul.c.
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 return1
- 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$
Solution: 4-add.c.
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
, printError
, followed by a new line, and return1
- 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$
Solution: 100-change.c.