What is a command line argument in C language?

An executable instruction that performs a task for OS is called a command. These commands are issued from the prompt of OS.

The arguments that are associated with the commands are as follows −

• argc - argument count.

• argv - argument vector.

argc − It holds the total number of arguments passed from the command prompt.

argv − It is a pointer to an array of character strings contains names of arguments.

For example,

c: |> sample. Exe hello how are you
   arguments

Here,

• argc = 5

• argv[0] = sample.exe

• argv[1] = hello

• argv [2] = how

• argv[3] = are

• argv[4] = you

Example

Following is the C program for command line argument −

#include<stdio.h>
main ( int argc, char *argv[ ]){
   int i;
   clrscr( );
   printf (" no. of arguments at command p = %d", argc);
   printf (" arguments given at prompt are 
");
   for ( i = 1; i <argc; i++)
      printf ("%s
 ", argv[i]);
   getch( );
}

Output

To run a C program with command-line arguments −

• Compile the program

• Run the program

• Go to the command prompt and give the input as shown below.

c:|> sample.exe hello how are you.
No. of arguments given at prompt is = 5
Arguments given at command prompt are:
hello
How

Are
You