zhoukuo

/* (char)i ? printf("l\n") : printf("b\n"); */
#include <stdio.h>
int byteorder(void)
{
	int i = 0x0001;
	(char)i ? printf("l\n") : printf("b\n");
	return i;
}

zhoukuo

/* use ftime() to calculate the execution time of millisecond */
#include <sys/timeb.h>
long timecost(void (*dosomething)())
{
	struct timeb begin, end;
	long cost;

	ftime(&begin);
	dosomething();
	ftime(&end);

zhoukuo

/* use gettimeofday() to calculate the execution time in microseconds */
#include <sys/time.h>
long timecost(void (*dosomething)())
{
	struct timeval start, end;
	long cost;

	gettimeofday(&start, NULL);
	dosomething();
	gettimeofday(&end, NULL);

zhoukuo

/* use time() to calculate the execution time in second */
#include <time.h>
long timecost(void (*dosomething)())
{
	time_t start, end;
	long cost;

	start = time(NULL);
	dosomething();
	end = time(NULL);

zhoukuo

/* use tolower() to convert string */
#include <ctype.h>
char* strlwr(char *s)
{
	char *d = s;
	while(*d)
		*d++ = tolower(*d);
	return s;
}

zhoukuo

/* use toupper() to convert string */
#include <ctype.h>
char* strupr(char *s)
{
	char *d = s;
	while(*d)
		*d++ = toupper(*d);
	return s;
}