20170912_字符串拷贝strcpy的实现

20170912_字符串拷贝strcpy的实现

//strcpy(des,src)实现了把从src地址开始的且含有'\0'结束符的字符串复制到//以des开始的地址空间内。#include<iostream>#include<cstdio>#include<cassert>using namespace std;char *strCpy(char *des, const char *src)//src参数不容改变,des要能改变，同时des空间要足够大！{                                           //假设不存在des长度小于src长度的情况，不然会出错！assert(des!=NULL && src!=NULL);char *address=des;while((*des=*src)!='\0'){++des;++src;}if((des+1)!=NULL)//src长度小于des的长度，那么原来的des后面的字符也要清空！{++des;while((*des)!='\0')*(des++)=NULL;}return address;//要有返回值}int main(){//char src[]="abcdef";/*char src[]="";*/char src[]="abcde";char des[100]="ABCDEFGHI";cout<<"Input string is: "<<des<<","<<src<<endl;char *res;res=strCpy(des,src);cout<<"strcpy result is: "<<res<<endl<<endl;cout<<(*(res+6))<<" "<<(*(res+10))<<" "<<sizeof(des)<<endl;system("pause");return 0;}