How to: Provide a command line argument in C

Question: “How do I read in input from a C program” or “How do I read input from the command line in C” ??

Answer: Easily

Aside from the usual inclusion of stdio.h and stdin.h you just have to loop through the char* array in main.

#include <stdlib.h>
#include <stdio.h>
int main(int argc, char* argv[])
    int i;
    printf ("Number of arguments provided: %d\nThey are:\n", argc);
    for(i=0;i<argc;i++) {
        printf ("%s\n",argv[i]);
    return 1;

The above snippet outputs the following:

./ProgramName MyArgument AnotherArgument
Number of arguments provided: 3
They are:

With the traditional C main method, argc gets the number of arguments provided at the command line. Also, this example assumes the name of the program is “ProgramName” (in C the program name is always the first argument).

Leave a Reply


Staypressed theme by Themocracy