学步园

下面是我觉得比较能够体现面试官意图的代码：

//
// 模拟 C 标准库函数 strcpy 的实现。
// 百度百科词条“strcat”有详细解说.
//

#include <cstdlib>
#include <cassert>
#include <iostream>
#include <exception>

// C++ 中推荐的常量定义方式.
const unsigned _MAX_STRING = 100;

char* strcpy(char* szDest, const char* szSrc)
{
    // 特殊情况的判断，我觉的使用断言比抛出异常好.
    assert(NULL != szDest && NULL != szSrc);

    char* pszDestCpy = szDest;

    while ('\0' != (*pszDestCpy++ = *szSrc++)) 
    { NULL; }
	
    return szDest;
}


//
// 测试.
//
int main(void)
{
    char szDest[_MAX_STRING] = {0};
    char szSrc[_MAX_STRING] = "I am a eternal newbie.";
	
    // char *szSrc = NULL;
	
    std::cout << "Original Destination: "	<< szDest << std::endl;
    std::cout << "Original Source: " 		<< szSrc << std::endl;
	
    std::cout << "Current Destination: "<< strcpy(szDest, szSrc) << std::endl;
    std::cout << "Current Source: "		<< szSrc << std::endl; 

    return EXIT_SUCCESS;
}