逆置字符串

1.输入字符串

char ch[]="";
gets(ch);

2.逆置

1.逆置整个字符串
reverse(char* left, char* right)
{
  while (left < right)
  {
    char tmp = *left;
    *left = *right;
    *right = tmp;
    left++;
    right--;
  }
}
2.逆置每个单词
    char* start = ch;
  while (*start)
  {
    char* end = start;
    //当*end==''时，前面为假，不进入循环
    //当*end==‘\0'时，前面为真，后面为假，不进入循环
    while (*end != ' ' && *end != '\0')
    {
      end++;
    }
    reverse(start, end - 1);
    //当end指向字符串结尾处的'\0'将不再向后移动
    if (*end != '\0')
    {
      end++;
    }
    start = end;
  }

3.输出

printf("%s\n",ch);

#include<stdio.h>
#include<string.h>
#include<assert.h>
void reverse(char* left, char* right)
{
  assert(left);
  assert(right);
  while (left < right)
  {
  char tmp = *left;
  *left = *right;
  *right = tmp;
  left++;
  right--;
  }
}
int main()
{
  char ch[] = " ";
  gets(ch);
  int len = strlen(ch);
  reverse(ch, ch + len - 1);
  char* start = ch;
  while (*start)
  {
  char* end = start;
  //当*end==''时，前面为假，不进入循环
  //当*end==‘\0'时，前面为真，后面为假，不进入循环
  while (*end != ' ' && *end != '\0')
  {
    end++;
  }
  reverse(start, end - 1);
  //当end指向字符串结尾处的'\0'将不再向后移动
  if (*end != '\0')
  {
    end++;
  }
  start = end;
  }
  printf("%s\n", ch);
  return 0;
}