C Command Line Arguments

Syntax

int main(int argc, char *argv[])

Example

#include <stdio.h>

int main(int argc, char *argv[]) {
   printf("Number of arguments passed: %d\n", argc);
   
   printf("Arguments passed: ");
   for(int i = 0; i < argc; i++) {
      printf("%s ", argv[i]);
   }
   return 0;
}

Output

$./example arg1 arg2 arg3 arg4
Number of arguments passed: 5
Arguments passed: ./example arg1 arg2 arg3 arg4

Explanation

Command-line arguments are used to pass information to a program when it is executed. In C, the main() function accepts two parameters: argc (argument count) and argv (argument vector).

The argc parameter specifies the number of command-line arguments passed to the program, while argv is a pointer to an array of strings that contain the arguments themselves.

Use

Command-line arguments can be used to provide input to a command-line utility or program, or to modify its behavior. They can also be used to specify file names, directories, or other settings.

Important Points

• Command-line arguments are passed to main() by the operating system.
• The argv parameter is an array of strings.
• The first element of argv is always the name of the program.
• The argc parameter specifies the number of elements in argv.
• Command-line arguments can be used to configure and customize program behavior.

Summary

C command-line arguments provide a way to pass information to a program when it is executed. The main() function accepts two parameters: argc (argument count) and argv (argument vector). argc specifies the number of command-line arguments passed to the program, while argv is an array of strings that contain the arguments themselves. Command-line arguments can be used to configure and customize program behavior, and are a useful way to provide input to command-line utilities and programs.