C语言实现字符串按单词翻转

实现字符串按单词翻转

两步翻转法 1.字符串整体翻转 2.每个单词翻转

比如要将I am student.按单词翻转，变为student. am I

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

void reverse_string1(char* left,char* right)
{
	char temp;
	while (left < right)
	{
		temp = *left;
		*left = *right;
		*right = temp;
		left++;
		right--;
	}
}

int main()
{
	char arr1[20] = {0};
	printf("请输入字符串：\n");
	gets(arr1);			//不能使用scanf，因为scanf遇到空格就输入结束了
	int len = strlen(arr1);
	reverse_string1(arr1,(arr1+len-1));	
	printf("整体逆序：%s\n", arr1);			//.tenduts ma I
	char* start = arr1;
	while (*start != '\0')
	{
		char* end = start;
		while (*end != ' ' && *end != '\0')
		{
			end++;
		}
		reverse_string1(start, end - 1);	//end找到空格的首地址，要减一才是一个单词的最后一个字符
		//如果是空格，则再找后面的单词，如果是'\0'，start = '\0'，退出循环
		if (*end == ' ')
		{
			start = end + 1;
		}
		else
		{
			start = end;	
		}
	}
	printf("每个单词逆序：%s\n", arr1);		//student. am I
	return 0;
}