Calculator using Classes in C++

Implementing a calculator in C++ using the concept of the classes.

Functions:

1. Addition of two numbers.
2. Difference between two numbers.
3. Product of two numbers.
4. Division of two numbers.

Approach:

1. Declare local variables a, b for two numeric values.
2. Enter the Choice.
3. Takes two numbers, a and b.
4. do-while jump to an operator selected by the user.
5. Display the operation result.
6. Exit

Examples:

Input: a = 5, b = 10, choice = 1
Output: Sum is 15

Input: a = 10, b = 4, choice  = 3
Output: Product is 40

Below is the C++ program implementation of the above approach-

C++

// C++ program to implement
// the above approach
#include <iostream>
#include <math.h>
using namespace std;

// Class calculator
class Calculator
{
   float a, b;
public:

    // Function to take input
    // from user
    void result()
    {
        cout << "Enter First Number: ";
        cin >> a;
        cout << "Enter Second Number: ";
        cin >> b;
    }

    // Function to add two numbers
    float add()
    {
        return a + b;
    }

    // Function to subtract two numbers
    float sub()
    {
        return a - b;
    }

    // Function to multiply two numbers
    float mul()
    {
        return a * b;
    }

    // Function to divide two numbers
    float div()
    {
        if (b == 0)
        {
            cout << "Division By Zero" <<
                     endl;
            return INFINITY;
        }
        else
        {
            return a / b;
        }
    }
};

// Driver code
int main()
{
    int ch;
    Calculator c;
    cout << "Enter 1 to Add 2 Numbers" <<
            "\nEnter 2 to Subtract 2 Numbers" <<
            "\nEnter 3 to Multiply 2 Numbers" <<
            "\nEnter 4 to Divide 2 Numbers" <<
            "\nEnter 0 To Exit";

    do
    {
        cout << "\nEnter Choice: ";
        cin >> ch;
        switch (ch)
        {
        case 1:

            // result function invoked
            c.result();

            // add function to calculate sum
            cout << "Result: " <<
                     c.add() << endl;
            break;
        case 2:

            // sub function to calculate
            // difference
            c.result();
            cout << "Result: " <<
                     c.sub() << endl;
            break;
        case 3:
            c.result();

            // mul function to calculate product
            cout << "Result: " <<
                     c.mul() << endl;
            break;
        case 4:
            c.result();

            // div function to calculate division
            cout << "Result: " <<
                     c.div() << endl;
            break;
        }

    } while (ch >= 1 && ch <= 4);

    return 0;
}

Output:

Addition of two numbers:

Subtraction of two numbers:

Multiplication of two numbers:

Division of two numbers:

Time complexity: O(1)
Auxiliary Space: O(1)