C++ Prompt User to continue or leave - c++

Question

Actually i was just trying my hands upon C++ and stopped at this particular problem where instead of program getting closed, it should ask the user whether he/she wants to continue or wants to exit. Now for what i understand, i wrote the do-while code in ending lines but its not working. Please gimme a solution to it. Thanks!!
#include<iostream>
#include<stdio.h>
#include<cstdlib>
#include<string>
using namespace std;
class Cal
{
public:
int Add(int a, int b)
{
int res;
res=(a+b);
cout << "Answer is " << a << "+" << b << "=" << res << endl;
}
int Sub(int a,int b)
{
int res;
res=(a-b);
cout << "Answer is " << a << "-" << b << "=" << res << endl;
}
int Mul(int a,int b)
{
int res;
res=(a*b);
cout << "Answer is " << a << "*" << b << "=" << res << endl;
}
int Div(int a,int b)
{
int res;
res=(a/b);
cout << "Answer is " << a << "/" << b << "=" << res << endl;
}
};
int main()
{
int first, second, res, operation;
cout<<"**********************************"<<endl;
cout<<"******* Simple Calculator ********"<<endl;
cout<<"**********************************"<<endl;
cout<<"Select the Operation: "<<endl;
cout<<"1. Addition"<<endl;
cout<<"2. Subtraction"<<endl;
cout<<"3. Multiplication"<<endl;
cout<<"4. Divison"<<endl;
cout<<"Choosen Operation is: ";
cin>>operation;
cout << "Enter the 1st Number: ";
cin>>first;
cout << "Enter the 2nd Number: ";
cin>>second;
switch(operation){
case 1:
Cal a;
a.Add(first,second);
break;
case 2:
Cal b;
b.Sub(first,second);
break;
case 3:
Cal c;
c.Mul(first,second);
break;
case 4:
Cal d;
d.Div(first,second);
break;
default:
cout<< "Please Enter a Operation";
break;
}
char ans;
do
{
cout<< "Do you want to continue (Y/N)?\n";
cout<< "You must type a 'Y' or an 'N' :";
cin >> ans;
}
while((ans !='Y')&&(ans !='N')&&(ans !='y')&&(ans !='n'));
}

Answer 1

The do while loop does not enclose the body to be repeated, i.e. the calculator part.
The condition in do while does not look correct.
I would try this.
int main() {
char ans = 'N';
do {
// calculator stuff, better to be in a separate function
cout << "Do you want to continue (Y/N)?\n";
cout << "You must type a 'Y' or an 'N' :";
cin >> ans;
} while ((ans == 'Y') || (ans == 'y'));
}