c++字符串拼接

使用append

string s1 = "Hello ";  
    string s2 = "World! ";  
    string s3 = " China";  
    string s4;  
    s4.append(s1);  
    cout<<s4.c_str()<<endl;  
    s4.append(s2);  
    cout<<s4.c_str()<<endl;  
    s4.append(s3);  
    cout<<s4.c_str()<<endl;