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Conditional Sum Based on User Input in C#

In this exercise, we will create a C# program that interacts with the user to perform conditional addition. The program will first prompt the user for a number. If the number is not zero, it will request a second number and display the sum of both values. However, if the first number is zero, the program will simply display "0" without requesting another number.

This exercise helps reinforce fundamental programming concepts such as user input handling, conditional statements (if-else), and displaying formatted output in C#.



Group

C# Flow Control Basics

Objective

The objective of this exercise is to develop a C# program that reads a number from the user. If the number is not zero, it asks for a second number and calculates their sum. If the first number is zero, it simply displays "0".

Write a C# program to ask the user for a number; if it is not zero, then it will ask for a second number and display their sum; otherwise, it will display "0".

Example C# Exercise

 Copy C# Code 
// First and Last Name: John Doe

using System;

namespace ConditionalSum
{
    class Program
    {
        // The Main method is where the program starts execution
        static void Main(string[] args)
        {
            // Declare a variable to store the first user input
            int firstNumber;

            // Prompt the user to enter the first number
            Console.Write("Enter a number: ");
            firstNumber = Convert.ToInt32(Console.ReadLine()); // Read input and convert to integer

            // Check if the first number is zero
            if (firstNumber == 0)
            {
                // If the number is zero, display "0" and exit
                Console.WriteLine("0");
            }
            else
            {
                // If the number is not zero, ask for a second number
                Console.Write("Enter another number: ");
                int secondNumber = Convert.ToInt32(Console.ReadLine()); // Read second input

                // Calculate and display the sum
                int sum = firstNumber + secondNumber;
                Console.WriteLine("The sum of {0} and {1} is {2}.", firstNumber, secondNumber, sum);
            }

            // Wait for user input before closing the console window
            Console.ReadKey(); // Keeps the console open until a key is pressed
        }
    }
}

 Output

//Example 1 (User enters a nonzero first number):
Enter a number: 7  
Enter another number: 3  
The sum of 7 and 3 is 10.  

//Example 2 (User enters zero as the first number):
Enter a number: 0  
0

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