strcpy实现

#include <iostream>
#include <stdio.h>

using namespace std;
char *_strcpy(char* des, char* src)
{
    if (des == NULL || src == NULL)
    {
        return 0;
    }
   // cout << (void*)des << endl;
   // cout << src << endl;
   // cout << *des << endl;
   // cout << *src << endl;
    int ret = 0;
    char* temp1 = des;
    char* temp2 = src;
    while (!(ret=*temp1 -*temp2) && *temp1)
    {
        temp1++;
        temp2++;
    }
    if (ret == 0)
    {
        return 0;
    }
    char* pIter = des;
    while ((*pIter++ = *src++) != '\0');
    return des;
}

int main()
{
    char a[] = "abc";
    char b[] = "abc4";
    char *c = _strcpy(a, b);

    return 0;
}

 如果有对 while ((*pIter++ = *src++) != '\0'); 不理解的，可以写成这样

while (*pIter != '\0')
{
   *++pIter = *++src;
}