Command Line Arguments in C programming

It is possible to pass arguments to C programs when they are executed. The brackets which follow main are used for this purpose. argc refers to the number of arguments passed, and argv[] is a pointer array which points to each argument which is passed to mainA simple example follows, which checks to see if a single argument is supplied on the command line when the program is invoked.
#include <stdio.>h
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");
}
Note that *argv[0] is the name of the program invoked, which means that *argv[1] is a pointer to the first argument supplied, and *argv[n] is the last argument. If no arguments are supplied, argc will be one. Thus for n arguments, argc will be equal to n + 1. The program is called by the command line:
$myprog  argument1
More clearly, Suppose a program is compiled to an executable program myecho and that the program is executed with the following command.
$myeprog aaa bbb ccc
When this command is executed, the command interpreter calls the main() function of the myprog program with 4 passed as the argc argument and an array of 4 strings as the argv argument.
argv[0]         -  "myprog"
argv[1]  -  "aaa"
argv[2]  -  "bbb"
argv[3]  -  "ccc"
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