// LeftRotateString.cpp : Defines the entry point for the console application.

//

// 《剑指Offer——名企面试官精讲典型编程题》代码

// 著作权所有者：何海涛

#include "stdafx.h"

#include "..\Utilities\StringUtil.h"

#include <string.h>

char* LeftRotateString(char* pStr, int n)

{

if(pStr != NULL)

{

int nLength = static_cast<int>(strlen(pStr));

if(nLength > 0 && n > 0 && n < nLength)

{

char* pFirstStart = pStr;

char* pFirstEnd = pStr + n - 1;

char* pSecondStart = pStr + n;

char* pSecondEnd = pStr + nLength - 1;

// 翻转字符串的前面n个字符

Reverse(pFirstStart, pFirstEnd);

// 翻转字符串的后面部分

Reverse(pSecondStart, pSecondEnd);

// 翻转整个字符串

Reverse(pFirstStart, pSecondEnd);

}

}

return pStr;

}

// ====================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 _tmain(int argc, _TCHAR* argv[])

{

Test1();

Test2();

Test3();

Test4();

Test5();

Test6();

return 0;

}