C++ - Simple Calculator

Simple Calculator in C++

Introduction

This document provides notes and explanations for a C++ Simple Calculator program. The calculator allows basic arithmetic operations such as addition, subtraction, multiplication, and division. The program uses basic input and output functionality, control structures, and functions to perform the operations.

Program Structure

The program structure is simple and includes the following components:

• Menu: A user-friendly interface to choose the operation.
• Input: User inputs two numbers for the calculation.
• Arithmetic Operations: The program performs addition, subtraction, multiplication, or division based on the user's choice.
• Error Handling: The program checks for division by zero.
• Loop: The program runs until the user decides to exit.

Key Concepts

• Basic Arithmetic Operations
• Control Structures (if-else, switch-case)
• User Input and Output
• Error Handling (for division by zero)

Code Explanation

Main Logic

The main logic of the program presents a menu, takes user input for the numbers, and performs the selected operation. The user is repeatedly asked for input until they choose to exit.

Menu

The program starts by displaying a menu with options to perform various arithmetic operations. The user can choose one of the following options:

• 1. Add
• 2. Subtract
• 3. Multiply
• 4. Divide
• 5. Exit

Code Example

The following code represents the basic structure of the Simple Calculator program:

#include 
using namespace std;

int main() {
    double num1, num2;
    char operation;
    bool running = true;

    while (running) {
        // Display menu
        cout << "Simple Calculator\n";
        cout << "Choose an operation:\n";
        cout << "1. Add\n";
        cout << "2. Subtract\n";
        cout << "3. Multiply\n";
        cout << "4. Divide\n";
        cout << "5. Exit\n";
        cout << "Enter your choice: ";
        cin >> operation;

        if (operation == '5') {
            running = false;
            cout << "Exiting the calculator.\n";
            break;
        }

        // Get numbers for the operation
        cout << "Enter two numbers: ";
        cin >> num1 >> num2;

        // Perform operation based on user choice
        switch (operation) {
            case '1':
                cout << "Result: " << num1 + num2 << endl;
                break;
            case '2':
                cout << "Result: " << num1 - num2 << endl;
                break;
            case '3':
                cout << "Result: " << num1 * num2 << endl;
                break;
            case '4':
                if (num2 != 0)
                    cout << "Result: " << num1 / num2 << endl;
                else
                    cout << "Error: Division by zero is not allowed.\n";
                break;
            default:
                cout << "Invalid choice! Please select a valid operation.\n";
        }

        // Ask user if they want to continue
        cout << "Do you want to perform another operation? (y/n): ";
        char continueChoice;
        cin >> continueChoice;
        if (continueChoice == 'n' || continueChoice == 'N') {
            running = false;
            cout << "Exiting the calculator.\n";
        }
    }

    return 0;
}
    

Explanation of Code

Let's break down the key parts of the program:

• Input of Numbers: The program prompts the user to input two numbers for the operation.
• Menu and Switch-Case: A menu is displayed, and the program uses a switch-case structure to perform the selected operation.
• Division by Zero: The program checks if the user is attempting to divide by zero. If so, an error message is shown.
• Repeat Operation: After completing an operation, the program asks if the user wants to perform another one. The loop continues until the user exits.
• Exit: When the user selects the option to exit (choice '5'), the loop ends, and the program terminates.

Menu Driven Program

The use of a loop and switch-case allows the program to remain menu-driven, meaning it can repeatedly execute operations based on user input until the user chooses to exit. The loop ensures a smooth and continuous user experience.

Improvement Ideas

Here are some ways to improve this calculator program:

• Add support for more advanced operations such as square root, power, modulus, etc.
• Allow input validation for incorrect or invalid entries (e.g., non-numeric inputs).
• Enhance the user interface with a more interactive design, possibly using a graphical interface in C++ (e.g., using libraries like SFML or Qt).
• Use functions for each arithmetic operation to organize the code better and make it more modular.

The C++ Simple Calculator program demonstrates the use of control structures like loops and switch-case statements, basic arithmetic operations, and input/output handling. This simple program is a great starting point for beginners to understand fundamental concepts in C++ programming.