倒置字符串

#include<stdio.h>
#include<string.h>
void reverse(char* left, char* right)
{
  while(left < right)
  {
    char temp = 0;
    temp = *left;
    *left = *right;
    *right = temp;
    left++;
    right--;  
  }
}
int main()
{
  char arr[100] = { 0 };
  //输入字符串
  gets(arr);
  //求字符串的长度
  int len = strlen(arr);
  //字符串整体逆置，确定左下标和右下标
  reverse(arr, arr + len - 1);  
  //每个单词逆置
  char* start = arr;
  while(*start)
  {
    char* end = start;
    while(*end != ' ' && *end != '\0')
    {
      end++;
    }
    reverse(start, end - 1);
    if(*end == ' ')
    {
      //说明后面还有未逆置的单词
      start = end + 1;
    }
    else
    {
      //遇到了'\0',不能再往后了
      start = end;
    } 
  }
  printf("%s\n", arr);
  return 0;
}