Command line arguments in c

C – Command line arguments

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Command line arguments in C:

      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:

C

#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; }

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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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