Positional patterns in C Sharp (C#) - Mini Project: Build & Apply

Using Positional Patterns in C#

📖 Scenario: You work at a delivery company that handles different types of packages. Each package has a type and a weight. You want to write a program that checks the package type and weight to decide how to handle it.

🎯 Goal: Build a C# program that uses positional patterns to check package details and print the handling instructions.

📋 What You'll Learn

Create a record type Package with two properties: Type (string) and Weight (int).

Create a variable package with specific values.

Create a variable maxWeight to set the weight limit.

Use a switch expression with positional patterns to decide the handling message.

Print the handling message.

💡 Why This Matters

🌍 Real World

Delivery companies often need to decide how to handle packages based on their type and weight. Using positional patterns helps write clear and concise code for these decisions.

💼 Career

Understanding positional patterns and switch expressions is useful for writing clean, readable C# code in many business applications, especially those involving data classification and decision making.

1

Create the Package record and a package instance

Create a record called Package with two properties: string Type and int Weight. Then create a variable called package and set it to new Package("Fragile", 15).

C Sharp (C#)

// Your code here

Need a hint?

Use the record keyword to create a simple data container with two properties.

2

Add a maxWeight variable

Add an integer variable called maxWeight and set it to 20.

C Sharp (C#)

record Package(string Type, int Weight);

Package package = new Package("Fragile", 15);

// Your code here

Need a hint?

This variable will be used to compare the package weight later.

3

Use a switch expression with positional patterns

Create a string variable called handling and set it using a switch expression on package. Use positional patterns to match Type and Weight as follows: if Type is "Fragile" and Weight is less than or equal to maxWeight, set handling to "Handle with care"; if Type is "Heavy" and Weight is greater than maxWeight, set handling to "Use forklift"; otherwise, set handling to "Standard handling".

C Sharp (C#)

record Package(string Type, int Weight);

Package package = new Package("Fragile", 15);

int maxWeight = 20;

// Your code here

Need a hint?

Use the switch expression with positional patterns and when clauses for conditions.

4

Print the handling message

Write a Console.WriteLine statement to print the handling variable.

C Sharp (C#)

record Package(string Type, int Weight);

Package package = new Package("Fragile", 15);

int maxWeight = 20;

string handling = package switch
{
    ("Fragile", var w) when w  "Handle with care",
    ("Heavy", var w) when w > maxWeight => "Use forklift",
    _ => "Standard handling"
};

// Your code here

Need a hint?

Use Console.WriteLine(handling); to show the result.