Question

give one example of command line argument

Answer 1

it should be noted that argv holds the name of the program itself and argv is a pointer to the first command line argument supplied and *argv is the latest argument.if no arguments are supplied.argv will bw one,and if you pass one argument the argc is set at 2

Answer 2

he command line arguments are handled using main() function arguments where argc refers to the number of arguments passed, and argv[] is a pointer array which points to each argument passed to the program. Following is a simple example which checks if there is any argument supplied from the command line and take action accordingly −

#include <stdio.h> int main( int argc, char *argv[] ) { if( argc == 2 ) { printf("The argument supplied is %s\n", argv[1]); } else if( argc > 2 ) { printf("Too many arguments supplied.\n"); } else { printf("One argument expected.\n"); } }

When the above code is compiled and executed with single argument, it produces the following result.

$./a.out testing The argument supplied is testing

When the above code is compiled and executed with a two arguments, it produces the following result.

$./a.out testing1 testing2 Too many arguments supplied.

When the above code is compiled and executed without passing any argument, it produces the following result.

$./a.out One argument expected

It should be noted that argv[0] holds the name of the program itself and argv[1] is a pointer to the first command line argument supplied, and *argv[n] is the last argument. If no arguments are supplied, argc will be one, and if you pass one argument then argc is set at 2.

You pass all the command line arguments separated by a space, but if argument itself has a space then you can pass such arguments by putting them inside double quotes "" or single quotes ''. Let us re-write above example once again where we will print program name and we also pass a command line argument by putting inside double quotes −

#include <stdio.h> int main( int argc, char *argv[] ) { printf("Program name %s\n", argv[0]); if( argc == 2 ) { printf("The argument supplied is %s\n", argv[1]); } else if( argc > 2 ) { printf("Too many arguments supplied.\n"); } else { printf("One argument expected.\n"); } }

When the above code is compiled and executed with a single argument separated by space but inside double quotes, it produces the following result.

$./a.out "testing1 testing2" Progranm name ./a.out The argument supplied is testing1 testing2