Arguments

Last updated on: 10 March, 2019
Compiled by: Evan Tay

In this section you will find my notes on command line arguments which are passed into the main() function.

Print out arguments

The example program below prints out all command line arguments passed into the main() function.

print-arguments.c

#include <stdio.h>

int main(int argc, char **argv) {
    for (int i = 0; i < argc; i++) {
        printf("%s\n", argv[i]);
    }
}

Key details:

• argc - the number of arguments passed into the program
• argv - the array of character pointers (strings) containing all arguments
• argv[0] - the first argument which is also the name of the program

To use:

• Enter the above code into a file (e.g. print-arguments.c).
• Compile the code with gcc print-arguments.c -o print-arguments.
• Run the executable with ./print-arguments test.

Stuff to try

• Run the executable with ./print-arguments $USER to pass in the environment variable USER.

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