这道题可分为两步：第一步将整个字符串全部倒置：!anihC morf ma I

第二步部分倒置，如果不是空格，则倒置单词

#include <stdio.h>
#include <string.h>

int main()
{
	int i = 0,j = 0;
	int begin = 0,end = 0;
	char str[] = "I am from China!",tmp;
	//char tmp;
	
	printf("--1--:str = %s\n",str);
	
	//第一步：全部翻转
	j = strlen(str) - 1;
	while(j > i)
	{
		tmp = str[i];
		str[i] = str[j];
		str[j] = tmp;
		j--;
		i++;
	}
	printf("--2--:str = %s\n",str);
	
	//第二步：将每个空格隔开的单词翻转
	i = 0;  //i = 0不能丢，要从头开始
	while(str[i])
	{
		if(str[i] != ' ')
		{
			begin = i;
			while(str[i] && str[i] != ' ')
			{
				i++;
			}
			i = i - 1;
			end = i;
		}
		
		while(end > begin)
		{
			tmp = str[begin];
			str[begin] = str[end];
			str[end] = tmp;
			end--;
			begin++;
		}
		
		i++;
	}
	
	printf("--3--:str = %s\n",str);
	
	return 0;
}