小技巧----“三步翻转法”
栏目：php教程时间：2016-06-07 08:16:47
例：实现字符串左移函数，比如"abcdefghi"循环左移3位就是”defghiabc".
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
#include<string.h>
void revers(char *left,char *right) //翻转函数，left代表起始位置，right代表结束位置
{
assert(left);
assert(right);
char tmp = 0;
while (left < right)
{
tmp = *left;
*left = *right;
*right = tmp;
left++;
right--;
}
}
void leftLoopMove(char *pStr, unsigned short steps)
{
assert(pStr);
int len = strlen(pStr);
steps = steps%len; //这样可以处理steps不合法的情况
revers(pStr,pStr+steps⑴); //首先翻转前steps个字符
revers(pStr + steps, pStr + len - 1); //再翻转剩下的字符
revers(pStr, pStr + len - 1); //再将整体翻转
}
int main()
{
char arr[50] = { 0 };
unsigned short steps = 0; //要右移的个数
scanf("%s%hd",arr,&steps);
leftLoopMove(arr,steps);
printf("%s\n", arr);
system("pause");
return 0;
}
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