不使用字符串处理的库函数，实现strcpy

来源：互联网发布：线刷宝刷机有垃圾软件编辑：程序博客网时间：2024/05/16 01:29

#include <stdio.h>#include <stdlib.h>int mstrlen(const char* p){    if(!p || *p == '\0')    {        return 0;    }else{        return mstrlen(p+1)+1;      }}char* mmemcpy(void *dest, const void *src, unsigned int len){    /*需要考虑到dest和src在堆区存在重叠的情况*/    void *ret = dest;    if(dest && src)     {        if((dest < src) || (((char *)dest > (char *)src)+len)){            while(len--){                *(char *)dest = *(char *)src;                   dest = (char *)dest + 1;                src = (char *)src + 1;            }        }else{            dest = (char *)dest + len -1;            src = (char *)src + len -1;            while(len--){                *(char *)dest = *(char *)src;                   dest = (char *)dest - 1;                src = (char *)src - 1;            }        }       }    return ret;}char* mstrcpy(char *dest, const char *src){    char *ret = dest;    if(dest && src)    {        mmemcpy(dest, src, mstrlen(src)+1);     }    return ret;}int main(void){    const char *src = "hello";    char *dest = malloc(sizeof(char)*6);    mstrcpy(dest, src);    printf("%s\n", dest);    return 0;}

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