#include<iostream>
#include<cstring>
#include<sstream>
using namespace std;
string a = "hello ";
string b = "world!";
string f1(){
return a + b;
}
string f2(){
string c;
c.append(a + b);
/*or
c.append(a);
c.append(b);
*/
return c;
}
string f3(){
stringstream ss;
ss<<a<<b;
return ss.str();
}
int main(){
//+
cout << f1() <<endl;
//append
cout << f2() << endl;
//sstream
cout << f3() << endl;
return 0;
}
运行结果
