Command line arguments in C language

Command line arguments in C Language:

main() function of a C program accepts arguments from command line or from other shell scripts by following commands. They are,

argc
argv[]

where,

argc - number of arguments in the command line including program name
argv[] – This is carrying all the arguments

In real time application, it will happen to pass arguments to the main program itself. These arguments are passed to the main () function while executing binary file from command line.
For example, when we compile a program (test.c), we get executable file in the name “test”.
Now, we run the executable “test” along with 4 arguments in command line like below.

test this is a program

Where,

argc             =       5
argv[0]         =       “test”
argv[1]         =       “this”
argv[2]         =       “is”
argv[3]         =       “a”
argv[4]         =       “program”
argv[5]         =       NULL

Example program for argc() and argv() functions in C Language:

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#include <stdio.h>

#include <stdlib.h>

int main(int argc, char *argv[])   //  command line arguments

{

if(argc!=5) 

{

   printf("Arguments passed through command line " \

          "not equal to 5");

   return 1;

}

   printf("\n Program name  : %s \n", argv[0]);

   printf("1st arg  : %s \n", argv[1]);

   printf("2nd arg  : %s \n", argv[2]);

   printf("3rd arg  : %s \n", argv[3]);

   printf("4th arg  : %s \n", argv[4]);

   printf("5th arg  : %s \n", argv[5]);

return 0;

}

Output:

Program name : test
1st arg : this
2nd arg : is
3rd arg : a
4th arg : program
5th arg : (null)

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