Enums in Blockchain / Solidity - Mini Project: Build & Apply

Using Enums in Blockchain Smart Contracts

📖 Scenario: You are building a simple blockchain smart contract to manage the status of a package delivery. The package can be in one of several states: Pending, Shipped, Delivered, or Returned.Using an enum helps keep track of these states clearly and safely.

🎯 Goal: Create a Solidity smart contract that uses an enum to represent package delivery status. You will set the initial status, update it, and then display the current status.

📋 What You'll Learn

Create an enum called Status with values Pending, Shipped, Delivered, and Returned.

Create a state variable called currentStatus of type Status.

Set the initial currentStatus to Pending.

Write a function to update currentStatus to Shipped.

Write a function to get the current status as a string.

Print the current status after updating it.

💡 Why This Matters

🌍 Real World

Enums help track fixed states like package delivery status, voting phases, or contract stages in blockchain smart contracts.

💼 Career

Understanding enums is essential for blockchain developers to write clear, safe, and maintainable smart contracts.

1

Create the Enum and State Variable

Create an enum called Status with values Pending, Shipped, Delivered, and Returned. Then create a public state variable called currentStatus of type Status and set it to Status.Pending.

Blockchain / Solidity

// Define the enum and state variable
// Your code here

Need a hint?

Use enum Status { Pending, Shipped, Delivered, Returned } to define the states. Then declare Status public currentStatus = Status.Pending;.

2

Add a Function to Update Status

Add a public function called shipPackage that sets currentStatus to Status.Shipped.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract PackageDelivery {
    enum Status { Pending, Shipped, Delivered, Returned }
    Status public currentStatus = Status.Pending;

    // Add shipPackage function here
    // Your code here
}

Need a hint?

Define function shipPackage() public and inside set currentStatus = Status.Shipped;.

3

Add a Function to Get Status as String

Add a public view function called getStatus that returns a string memory representing the current status. Use if or else if statements to check currentStatus and return the matching string: "Pending", "Shipped", "Delivered", or "Returned".

Blockchain / Solidity

pragma solidity ^0.8.0;

contract PackageDelivery {
    enum Status { Pending, Shipped, Delivered, Returned }
    Status public currentStatus = Status.Pending;

    function shipPackage() public {
        currentStatus = Status.Shipped;
    }

    // Add getStatus function here
    // Your code here
}

Need a hint?

Use if statements to compare currentStatus with each Status value and return the corresponding string.

4

Print the Current Status

Write a public view function called printStatus that returns the current status string by calling getStatus(). This simulates printing the status.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract PackageDelivery {
    enum Status { Pending, Shipped, Delivered, Returned }
    Status public currentStatus = Status.Pending;

    function shipPackage() public {
        currentStatus = Status.Shipped;
    }

    function getStatus() public view returns (string memory) {
        if (currentStatus == Status.Pending) {
            return "Pending";
        } else if (currentStatus == Status.Shipped) {
            return "Shipped";
        } else if (currentStatus == Status.Delivered) {
            return "Delivered";
        } else {
            return "Returned";
        }
    }

    // Add printStatus function here
    // Your code here
}

Need a hint?

Create function printStatus() public view returns (string memory) and return the result of getStatus().