解答编程题

Ⅰ c++语言编程题两题，希望高手帮解答一下，谢谢！

第一题：

#include<iostream>
#include<cstring>

usingnamespacestd;

classString
{

friendostream&operator<<(ostream&output,String&a);
friendintmain();

private:
intsize;
char*str;
public:
String(char*a);
};

String::String(char*a)
{
str=a;
size=strlen(a);
}

ostream&operator<<(ostream&output,String&a)
{
inti;
intn=a.size;
for(i=0;i<n;i++){
output<<a.str[i];
}
returnoutput;
}

intmain()
{
char*a="Helloworld!";
cout<<a<<endl;
Strings=String(a);
cout<<s;
cin.get();
return0;
}