Command Line Arguments

Program #1: Echo, Version 1

This program echos its command line arguments on a separate line..



/*

 * print arguments followed by a newline

 */

#include <stdio.h>



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

{

	int i;					/* counter in a for loop */



	/*

	 * go through the argument list, skipping arg 0 (it's

	 * the program name)

	 */

	for(i = 1; i < argc-1; i++)

		printf("%s ", argv[i]);



	/*

	 * now print the last argument, UNLESS it is arg 0

	 */

	if (argc > 1)

		printf("%s\n", argv[argc-1]);



	/*

	 * return success!

	 */

	return(0);

}





Program #2: Echo, Version 2

This also echos its command line arguments, but if the first argument is -n, it suppresses the trailing newline and 
does not print that argument.



#include <stdio.h>



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

{

	int prnl = 1;					/* 1 to print newline, 0 not to */

	int i;					/* counter in a for loop */



	/*

	 * if argument 0 is -n, set prnl to suppress newline

	 * skip it in the rinting; otherwise, print beginning with arg 1

	 */

	if (argc > 1 &&

		argv[1][0] == '-' && argv[1][1] == 'n' && argv[1][2] == '\0'){

		prnl = 0;

		i = 2;

	}

	else

		i = 1;



	/*

	 * go through the argument list, skipping arg 0 (it's

	 * the program name) and arg 1 if needed

	 */

	for( ; i < argc-1; i++)

	printf("%s ", argv[i]);



	/*

	 * now print the last argument, UNLESS it is arg 0, or arg 1 and -n

	 */

	if ((prnl && argc > 1) || (!prnl && argc > 2)){

		printf("%s", argv[argc-1]);

		/* put out the newline */

		if (prnl)

			putchar('\n');

	}



	/*

	 * return success!

	 */

	return(0);

}