c++字符串等长替换函数

// Replace.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <shlwapi.h>
#pragma comment(lib,"shlwapi.lib")
int StrReplaceI(char* src,char* oldstr,char* newstr)
{

    if (!src)
    {
        return 1;
    }
    int oldlen=strlen(oldstr);
    int newlen=strlen(newstr);
    if (newlen>oldlen)
    {
        return 2;
    }
    char *pold=StrStrI(src,oldstr);
    if (!pold)
    {
        return 3;
    }
    memset(pold,' ',oldlen);
    memcpy(pold,newstr,newlen);
    return 0;
}
int main(int argc, char* argv[])
{
    printf("Hello World!\n");
    char buf[]="1234 567 890";

    StrReplaceI(buf,"567","99");
    printf("%s\n",buf);
    
    return 0;
}