左旋转字符串

来源：互联网发布：人工智能会取代人类吗编辑：程序博客网时间：2024/04/29 11:46

题目描述

汇编语言中有一种移位指令叫做循环左移（ROL），现在有个简单的任务，就是用字符串模拟这个指令的运算结果。对于一个给定的字符序列S，请你把其循环左移K位后的序列输出。例如，字符序列S=”abcXYZdef”,要求输出循环左移3位后的结果，即“XYZdefabc”。是不是很简单？OK，搞定它！

#include <iostream>using namespace std;void Reverse(char* pBegin, char* pEnd){if(pBegin == NULL || pEnd == NULL)return;while(pBegin < pEnd){char temp = *pBegin;*pBegin = *pEnd;*pEnd = temp;pBegin++;pEnd--;}}

char* LeftRotateString(char* str, int n){if(str != NULL){int length = strlen(str);if(length > 0 && n > 0 && length > n){char* pBegin = str;char* pStr = str + n -1;char* pEnd = str + length -1;Reverse(pBegin, pStr);Reverse(pStr+1, pEnd);Reverse(pBegin, pEnd);}}return str;}

// ====================测试代码====================void Test(char* testName, char* input, int num, char* expectedResult){    if(testName != NULL)        printf("%s begins: ", testName);    char* result = LeftRotateString(input, num);    if((input == NULL && expectedResult == NULL)        || (input != NULL && strcmp(result, expectedResult) == 0))        printf("Passed.\n\n");    else        printf("Failed.\n\n");}// 功能测试void Test1(){    char input[] = "abcdefg";    char expected[] = "cdefgab";    Test("Test1", input, 2, expected);}// 边界值测试void Test2(){    char input[] = "abcdefg";    char expected[] = "bcdefga";    Test("Test2", input, 1, expected);}// 边界值测试void Test3(){    char input[] = "abcdefg";    char expected[] = "gabcdef";    Test("Test3", input, 6, expected);}// 鲁棒性测试void Test4(){    Test("Test4", NULL, 6, NULL);}// 鲁棒性测试void Test5(){    char input[] = "abcdefg";    char expected[] = "abcdefg";    Test("Test5", input, 0, expected);}// 鲁棒性测试void Test6(){    char input[] = "abcdefg";    char expected[] = "abcdefg";    Test("Test6", input, 7, expected);}int main(int argc, char* argv[]){    Test1();    Test2();    Test3();    Test4();    Test5();    Test6();    return 0;}

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