Calculator project problem

Hey! I have written a code for the calculator. But you can not tell me the reason. Thank you for your help.

<#include <iostream
using namespace std;

int main(int argc, char** argv) {
float firstNumber, secondNumber, result;
char op;
cout<<“Lotfan ebarat mohasebati mored nazar ra vaared konid va sepas Enter ra feshar dahid”<<endl;
cout<<“Mesal: 3.5 * 5”<<endl;
cin>>firstNumber>>op>>secondNumber;

switch(op){
    case '+':
        result = firstNumber + secondNumber;
        break;
    case '-':
        result = firstNumber - secondNumber;
        break;
    case '*':
        result = firstNumber * secondNumber;
        break;
    case '/':
        result = firstNumber / secondNumber;
        break;
    default:
        cout<<"Error"<<endl;
     
}

cout<<firstNumber<<" "<<op<<" "<<secondNumber<<" = "<<result;

return 0;

}>

Source used: ghasedak24