no match for 'operator==' in 'operation == addition'?

[JoorDovah]

I am creating a simple calculator with all operations, but it's not working!
Here is my code:

//The Calculator
#include <iostream>
#include <string>
#include <sstream>

using namespace std;

int addition(float a, int b)
{
    float result;
    result = a+b;
    return result;
}

int multiplication(float a, float b)
{
    float result;
    result = a*b;
    return result;
}

int division(float a, float b)
{
    float result;
    result = a/b;
    return result;
}

int subtraction(int a, int b)
{
    int result;
    result = a-b;
    return result;
}

int remainder(float a, float b)
{
    float result;
    result = a*b;
    return result;
}


int main()
{
    cout << "Which operation do you want to calculate? There is addition, subtraction, multiplication, division and remainder.";
    string operation;
    getline(cin,operation);
    if (operation == addition)
        cout << "You chosen addition.";

    else if (operation == subtraction)
        cout << "You chosen subtraction";

    else if (operation == multiplication)
        cout << "You chosen multiplication.";

    else if (operation == division)
        cout << "You chosen division.";

    else if (operation == remainder)
        cout << "You chosen to find the remainder.";

    else
        cout << "You typed something else. Terminating program...";
        return 0;
}

I even tried using type instead of operation. It pops up with this error message:
no match for 'operator==' in 'operation == addition'
What is wrong with this code and what can I do to fix it?

[TarikNeaj]

You can't compare a string with a function.

I would recommend you make a menu instead. Then using if statements or a switch case, you can determine what the user chose.

int choice;
cin >> choice;

Present menu:
1. Addition
2. Multiplication
3. Subtraction
4. Division

if(choice == 1)
    cout << "You chose Addition";

[Chervil]

What is addition here?
if (operation == addition)

You could try

    if (operation == "addition")

though as an end-user of a calculator, I'd prefer a single character such as

    if (operation == "+")

[JoorDovah]

Thanks, Tarik!