/*
 * Copyright(C) Paul und Scherer (mct.de/mct.net)
 *
 * This example demonstrates how to...
 *
 *  ... measure program execution time.
 */

#include <stdio.h>
#include <time.h>

/*
 * You are prompted for a count, then the program
 * measures the time it takes to execute an empty
 * loop count times.
 */
int
main(void)
{
	while (1) {
		clock_t start, stop;		/* start/stop */
		char line[20];			/* input buffer */
		unsigned long count;		/* loop count */

		fputs("Enter loop count: ", stdout);
		fgets(line, sizeof(line), stdin);
		if (sscanf(line, "%lu", &count) != 1) continue;
		fputs("Looping... ", stdout), fflush(stdout);

		start = clock();		/* clocks at start */
		while (count--) ;		/* loop... */
		stop = clock();			/* clocks at stop */

		printf("%lums (+/-%dms)\n\n",
			(stop-start)*1000 /CLOCKS_PER_SEC,
		   (CLOCKS_PER_SEC/2+1000)/CLOCKS_PER_SEC
		);
	}
}