strcpy

char * strcpy(char * strDest,const char * strSrc);

char * strcpy(char * strDest,const char * strSrc)
{
char * strDestCopy = strDest; //[3]
if ((NULL==strDest)||(NULL==strSrc)) //[1]
throw "Invalid argument(s)"; //[2]
while ((*strDest++=*strSrc++)!=‘\0‘); //[4]
return strDestCopy;
}

int iLength=strlen(strcpy(strA,strB));

char * strA=strcpy(new char[10],strB);

while ((*strDestCopy++=*strSrc++)!=‘\0‘）;

while( 1 ){ 
    char temp; 
    temp = *strDestCopy = *strSrc;
    strDestCopy++; strSrc++;
    if( ‘\0‘ == temp )
        break;
}    

while ( *strSrc != ‘\0‘ )
{
     *strDestCopy = *strSrc; 
    strDestCopy++; 
    strSrc++;
}
*strDestCopy=*strSrc;

#include<iostream>
#include<stdlib.h>
using namespace std;
char * strcpy( char * strDest, const char * strSrc ){
char * strDestCopy = strDest;
if ((NULL==strDest)||(NULL==strSrc)) throw "Invalid argument";
while ( (*strDest++=*strSrc++) != ‘\0‘ );
return strDestCopy;
}
void main( int argc, char * argv[] ){
char a[20], c[] = "i am teacher!";
try{
strcpy(a,c);
}
catch(char* strInfo) {
cout << strInfo << endl;
exit(-1);
}
cout << a << endl;
}

#include<iostream>
using namespace std;
char *strcpy(char *strDes, const char *strSrc); //函数声明
int main(){
const char *strSrc="helloworld";;
char *strDes=NULL;
strDes=strcpy(strDes,strSrc);
cout<<"strSrc="<<strSrc<<endl;
cout<<"strDes="<<strDes<<endl;
if(strDes!=NULL){
free(strDes);
strDes=NULL;
}
return 0;
}
char *strcpy(char *strDes, const char *strSrc){
assert(strSrc!=NULL); //若strSrc为NULL，则抛出异常。
strDes=(char *)malloc(strlen(strSrc)+1); //多一个空间用来存储字符串结束符‘\0‘
char *p=strDes;
while(*strSrc!=‘\0‘){
*p++=*strSrc++;
}
*p=‘\0‘;
return strDes;
}

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char* p="how are you ?";
char name[20]="ABCDEFGHIJKLMNOPQRS";
strcpy(name,p); //name改变为"how are you ? "====>正确！
strncpy(name,p, sizeof(name));//name改变为"how are you ?"=====>正确！后续的字符将置为NULL

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char* p="how are you ?";
char name[10];
strcpy(name,p); //目标串长度小于源串,错误！
name[sizeof(name)-1]=‘\0‘; //和上一步组合，弥补结果，但是这种做法并不可取，因为上一步出错处理方式并不确定
strncpy(name,p,sizeof(name)); //源串长度大于指定拷贝的长度sizeof(name)，注意在这种情况下不会自动在目标串后面加‘\0‘
name[sizeof(name)-1]=‘\0‘; //和上一步组合，弥补结果