What are command line arguments? Explain with the help of a suitable example.

 

DOEACC

[M3-R4: PROGRAMMING AND PROBLEM SOLVING THROUGH ‘C’ LANGUAGE]

[ July, 2010 (New)]

 

Q.What are command line arguments? Explain with the help of a suitable example.

Answer:

Command line arguments are values provided to a program at the time of its execution through the command line or terminal. When you run a program from the command line, you can pass additional information to the program by including command line arguments after the program name. These arguments are accessed by the program and can be used to influence its behavior or provide input data.

In C, the main function can take two arguments: argc (argument count) and argv (argument vector).

argc: It represents the number of command line arguments passed to the program, including the program name itself.

argv: It is an array of strings (character pointers) that contains the actual command line arguments. The first element argv[0] is the name of the program.

Here's a simple example in C to illustrate command line arguments:

#include <stdio.h>

int main(int argc, char *argv[]) {
    // Check if there are at least two arguments (including the program name)
    if (argc < 2) {
        printf("Usage: %s <name>\n", argv[0]);
        return 1; // Exit the program with an error code
    }

    // Print a greeting using the provided name
    printf("Hello, %s!\n", argv[1]);

    return 0; // Exit the program successfully
}

 

In this example, the program expects at least one command line argument (in addition to the program name). If the user doesn't provide the expected argument, the program prints a usage message. If an argument is provided, the program uses it to greet the user.

Here's how you might run this program from the command line: 

./greet John

In this example, "greet" is the name of the compiled program, and "John" is the command line argument. The program would then output:

Hello, John!