如果统计语句不起作用

我试图根据给出的用户输入让 if 语句为真或假，但是当我输入条件时，它说这对二进制表达式的操作数无效 （"字符串"（又名"basic_string"）和"int"）

这是我的代码

#include <iostream>
#include <string>

using namespace std;
 int main()
 {
 cout << "   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX" << endl;
 cout << "   X                                             X" << endl;
 cout << "   X                    MENU                     X" << endl;
 cout << "   X                                             X" << endl;
 cout << "   X       Press 1 to Play The Word Game.        X" << endl;
 cout << "   X                                             X" << endl;
 cout << "   X       Press 2 Too See a calculator.         X" << endl;
 cout << "   X                                             X" << endl;
 cout << "   X                                             X" << endl;
 cout << "   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX" << endl
 << endl;
string userinput;
cin >> userinput;
if (userinput == 1);{
    while (1<2)
    {
        cout << "Enter the Word." << endl;
        string UserInput;
        cin >> UserInput;
        cout << endl << UserInput << " is is not the right word but keep on trying" << endl << endl;
        cout << "Press Enter to Continue.";
        cin.clear();
        cin.ignore(255, 'n');
        cin.get();
        return 0;
    }
}
  if (userinput == 2);
  {   int z;
    int x;
    int sum;
    cout << " welcome to the calculator" << endl << endl;
    cin.clear();
    cin.ignore(255, 'n');
    cin.get();
    cout << "enter your first number";
    cin >> z; cout << endl << endl;
    cout << "enter your second number" << endl;
    cin >> x; cout << endl << endl;
    sum = z + x;
    cout << sum;
 }
cin.clear();
cin.ignore(255, 'n');
cin.get();
return 0;
}