Comparing a string in an If statement raises error

I am new to C++ (Coming from python). When I am comparing a string in an If statement it is always false.

#include <iostream>
#include <string>
using namespace std;
int main(){
 string op;
 int num1;
 int num2;
 cout << "Operator? ('+', '-', '*', '/' )" << endl;
 cin >> op;
 cout << "Number 1?" << endl;
 cin >> num1;
 cout << "Number 2?" << endl;
 cin >> num2;
 int result;
 cout << op << endl;
 if (op == +){
   int result = num1 + num2;
 }
 if (op == "-"){
  int result = num1 - num2;
 }
 if (op == "*"){
  int result = num1 * num2;
 }
 if (op == "/"){
  int result = num1 / num2;
 }
 else{
  cout << "Invalid Operator" << endl;
  return 0;
 }
 cout << "Result is " << result << endl;
}

When I feed it the inputs '+', '1', and '1', It prints '+', meaning it read the input. But then I expect it to give me 'The result is 2', but it prints "Invalid operator". What can i do to fix this?