将字符串中的\t替换为4个空格

#include<iostream>
using namespace std;
int main(int argc, _TCHAR* argv[])
{
    char *s = "hello\t\tworld";
    cout<<s<<endl;
    char *s1 = new char[strlen(s)+1];
    char *temp = s1;
    while(*s!='\0'){
        if(*s!='\t'){
            *s1=*s;
            s1++;
            s++;
        }
        if(*s=='\t'){
            memset(s1,' ',4);
            s1+=4;
            s++;
        }
    }
    s1[strlen(s)+1]='\0';
    cout<<temp<<endl;
}