字符串左旋

题目描述：

定义字符串的左旋转操作：把字符串前面的若干个字符移动到字符串的尾部，如把字符串abcdef左旋转2位得到字符串cdefab。

#include<stdio.h> #include<string.h> char * invert(char * start, char * end){char tmp, *ptmp = start;while (start != NULL && end != NULL && start < end){tmp = *start;*start = *end;*end = tmp;start++;end--;}return ptmp;}char * left(char *s, int pos){int len = strlen(s);invert(s, s + (pos - 1));invert(s + pos, s + (len - 1));invert(s, s + (len - 1));return s;}int main(){char s[] = "abcdefghij";puts(left(s, 3));getchar();return 0;}