Calculator - If - C# Programming Exercise

This C# programming exercise requires creating a program that asks the user for two numbers and an operation to perform on them. The supported operations are +, -, *, x (multiplication), and / (division). The program will display the result of the chosen operation as shown in the example:

Example: Enter the first number: 5 Enter operation: + Enter the second number: 7 Result: 5+7=12

In this C# exercise, the use of if statements is mandatory to evaluate and execute the corresponding operation. The use of switch is not allowed. This reinforces essential skills in condition evaluation and handling mathematical operations in C#.

 Category

Basic Data Types

 Exercise

Calculator - If

 Objective

Write a C# program that asks the user for two numbers and an operation to perform on them (+,-,*,x,/) and displays the result of that operation, as in this example:

Enter the first number: 5
Enter operation: +
Enter the second number: 7
5+7=12

Note: You MUST use "if", not "switch"

 Write Your C# Exercise

using System;  // Import the System namespace to use basic classes like Console

class Program  // Define the main class of the program
{
    static void Main()  // The entry point of the program
    {
        double num1, num2, result;  // Declare variables for two numbers and the result
        string operation;  // Declare a variable to store the operation

        // Ask the user for the first number
        Console.Write("Enter the first number: ");
        num1 = Convert.ToDouble(Console.ReadLine());  // Read and convert the input to double

        // Ask the user for the operation
        Console.Write("Enter operation (+, -, *, x, /): ");
        operation = Console.ReadLine();  // Read the operation as a string

        // Ask the user for the second number
        Console.Write("Enter the second number: ");
        num2 = Convert.ToDouble(Console.ReadLine());  // Read and convert the second number to double

        // Perform the operation using "if"
        if (operation == "+")  // Check if the operation is addition
        {
            result = num1 + num2;  // Perform addition
            Console.WriteLine($"{num1} + {num2} = {result}");  // Display the result
        }
        else if (operation == "-")  // Check if the operation is subtraction
        {
            result = num1 - num2;  // Perform subtraction
            Console.WriteLine($"{num1} - {num2} = {result}");  // Display the result
        }
        else if (operation == "*" || operation == "x")  // Check if the operation is multiplication (consider both '*' and 'x')
        {
            result = num1 * num2;  // Perform multiplication
            Console.WriteLine($"{num1} * {num2} = {result}");  // Display the result
        }
        else if (operation == "/")  // Check if the operation is division
        {
            if (num2 != 0)  // Check if the divisor is not zero
            {
                result = num1 / num2;  // Perform division
                Console.WriteLine($"{num1} / {num2} = {result}");  // Display the result
            }
            else  // If the divisor is zero
            {
                Console.WriteLine("Error: Cannot divide by zero.");  // Display an error message
            }
        }
        else  // If the operation is not recognized
        {
            Console.WriteLine("Invalid operation. Please use +, -, *, x, or /.");  // Display an error message
        }
    }
}

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