Help improve this calculator

[HuntedHD]

I'm an ultimate beginner of C++. How do i make this calculator restart without re-running it? I heard of loops, but I'm still not sure how to use those. also, are there any ways to make this calculator more simple? instead of adding many if statements?

#include <iostream>

using namespace std;

int a;
int b;
string symbol;
int sum;

int main()
{
    cout << "Hello and thank you for using this Calculator! \n\n";

    cout << "Enter a number(s) \n";
    cin >> a;
    cout << " \n";

    cout << "Now enter a symbol (+,-,*,%) \n";
    cin >> symbol;
    cout << " \n";

    cout << "Enter another number(s) \n";
    cin >> b;
    cout << " \n";

    if(symbol == "+"){

        sum = a+b;
        cout << "The answer is ";
        cout << sum;
    }else if(symbol == "-"){

            sum = a-b;
        cout << "The answer is ";
        cout << sum;

    }else if(symbol == "*"){

            sum = a*b;
        cout << "The answer is ";
        cout << sum;

    }else if(symbol == "%"){

            sum = a%b;
        cout << "The answer is ";
        cout << sum;
    }

    return 0;
}

[TheGrayWolf]

You can make it simpler by using switch statement, a char for the operation and just validate your input as you go

 
    int num1, num2, sum;
    char op;

    while (std::cin >> num1 >> op >> num2)
    {
        switch (op)
        {
            case '+':
                sum = num1 + num2;
                break;

            case '-':
                sum = num1 - num2;
                break; 
        }

        // /, *, ... 

        std::cout << sum << std::endl;
    }

[HuntedHD]

Thanks, ill try that!