Decision-Making Statements in C# Programming

Introduction

Decision-making statements in C# allow the program to make choices and execute specific blocks of code based on certain conditions. The most commonly used decision-making statements are if, else if, else, and switch-case.

If, Else If, Else Statements

The if, else if, and else statements are used to execute code based on one or more conditions.

Syntax

    if (condition)
    {
        // Code to execute if the condition is true
    }
    else if (another_condition)
    {
        // Code to execute if the previous condition is false and this one is true
    }
    else
    {
        // Code to execute if all conditions are false
    }
        

Example: Basic If Statement

    using System;
   class Program
    {
        static void Main()
        {
            int number = 10;
           if (number > 5)
            {
                Console.WriteLine("The number is greater than 5.");
            }
        }
    }
        

Output:

    The number is greater than 5.
        

Example: If-Else Statement

    using System;
   class Program
    {
        static void Main()
        {
            int number = 3;
           if (number > 5)
            {
                Console.WriteLine("The number is greater than 5.");
            }
            else
            {
                Console.WriteLine("The number is 5 or less.");
            }
        }
    }
        

Output:

    The number is 5 or less.
        

Example: If-Else If-Else Statement

    using System;
   class Program
    {
        static void Main()
        {
            int number = 15;
           if (number > 20)
            {
                Console.WriteLine("The number is greater than 20.");
            }
            else if (number > 10)
            {
                Console.WriteLine("The number is greater than 10 but 20 or less.");
            }
            else
            {
                Console.WriteLine("The number is 10 or less.");
            }
        }
    }
        

Output:

    The number is greater than 10 but 20 or less.
        

Switch-Case Statement

The switch-case statement is used for selecting one block of code from multiple options. It is more efficient than multiple if-else if statements when dealing with multiple discrete values.

Syntax

    switch (expression)
    {
        case value1:
            // Code to execute for value1
            break;
        case value2:
            // Code to execute for value2
            break;
        default:
            // Code to execute if no case matches
            break;
    }
        

Example: Switch-Case Statement

    using System;
   class Program
    {
        static void Main()
        {
            int day = 3;
           switch (day)
            {
                case 1:
                    Console.WriteLine("Monday");
                    break;
                case 2:
                    Console.WriteLine("Tuesday");
                    break;
                case 3:
                    Console.WriteLine("Wednesday");
                    break;
                case 4:
                    Console.WriteLine("Thursday");
                    break;
                case 5:
                    Console.WriteLine("Friday");
                    break;
                default:
                    Console.WriteLine("Weekend");
                    break;
            }
        }
    }
        

Output:

    Wednesday
        

Example: Switch-Case with String

    using System;
   class Program
    {
        static void Main()
        {
            string fruit = "Apple";
           switch (fruit)
            {
                case "Apple":
                    Console.WriteLine("You chose Apple.");
                    break;
                case "Banana":
                    Console.WriteLine("You chose Banana.");
                    break;
                default:
                    Console.WriteLine("Unknown fruit.");
                    break;
            }
        }
    }
        

Output:

    You chose Apple.
        

Key Points

• The if, else if, and else statements are useful for conditional execution of code based on ranges or complex conditions.
• The switch-case statement is ideal for selecting among multiple discrete values.
• Always include a default case in switch-case to handle unexpected values.

Conclusion

Decision-making statements like if, else if, else, and switch-case are essential for writing dynamic and flexible C# programs. Understanding their usage helps in implementing conditional logic effectively.