#include <iostream>
using namespace std;

// Function declarations
double add(double a, double b);
double subtract(double a, double b);
double multiply(double a, double b);
double divide(double a, double b);

int main() {
    double num1, num2;
    char operation;
    
    cout << "Enter first number: ";
    cin >> num1;
    cout << "Enter second number: ";
    cin >> num2;
    cout << "Enter operation (+, -, *, /): ";
    cin >> operation;
    
    switch(operation) {
        case '+':
            cout << "Result: " << add(num1, num2) << endl;
            break;
        case '-':
            cout << "Result: " << subtract(num1, num2) << endl;
            break;
        case '*':
            cout << "Result: " << multiply(num1, num2) << endl;
            break;
        case '/':
            if(num2 != 0) {
                cout << "Result: " << divide(num1, num2) << endl;
            } else {
                cout << "Error: Division by zero!" << endl;
            }
            break;
        default:
            cout << "Invalid operation!" << endl;
    }
    
    return 0;
}

// Function definitions
double add(double a, double b) {
    return a + b;
}

double subtract(double a, double b) {
    return a - b;
}

double multiply(double a, double b) {
    return a * b;
}

double divide(double a, double b) {
    return a / b;
}
    

1. What Is A Simple Calculator In C++ Using Functions?

A Simple Calculator In C++ Using Functions is a programming implementation that performs basic arithmetic operations (addition, subtraction, multiplication, division) using separate functions for each operation, demonstrating modular programming principles in C++.

2. How Does The Calculator Work?

The calculator implementation follows a structured approach:

Function Structure:

• Separate functions for each arithmetic operation
• Main function handles user input and operation selection
• Switch-case structure for operation routing
• Error handling for division by zero

Programming Concepts: The implementation demonstrates function declaration, definition, parameter passing, return values, and basic input/output operations in C++.

3. Importance Of Function-Based Implementation

Details: Using functions promotes code reusability, modularity, and maintainability. Each function has a single responsibility, making the code easier to debug, test, and extend with additional operations.

4. Using The Calculator

Tips: Enter two numbers and select the desired operation. The calculator will perform the arithmetic operation and display the result. For division, ensure the second number is not zero to avoid errors.

5. Frequently Asked Questions (FAQ)

Q1: Why use functions instead of writing all code in main?
A: Functions promote code organization, reusability, and make the program easier to maintain and debug.

Q2: Can I add more operations to this calculator?
A: Yes, you can easily extend it by adding new functions and including them in the switch-case structure.

Q3: What are the benefits of modular programming?
A: Modular programming makes code more readable, testable, and maintainable by separating concerns into distinct functions.

Q4: How does error handling work in this implementation?
A: The calculator includes basic error handling for division by zero, preventing runtime errors.

Q5: Can this calculator handle decimal numbers?
A: Yes, the calculator uses double data type which supports decimal numbers and precise calculations.