Contract inheritance in Blockchain / Solidity - Mini Project: Build & Apply

Contract inheritance

📖 Scenario: You are building a simple blockchain project where you want to reuse code from one contract in another. This is like inheriting traits from a parent in real life. You will create a base contract with some data and then a child contract that inherits from it and adds more features.

🎯 Goal: Build two Solidity contracts where one contract inherits from another. The child contract should access and use the data from the parent contract.

📋 What You'll Learn

Create a base contract called ParentContract with a public string variable greeting set to 'Hello from Parent'.

Create a child contract called ChildContract that inherits from ParentContract.

Add a public function getGreeting in ChildContract that returns the greeting string from ParentContract.

Deploy and call getGreeting to see the inherited greeting.

💡 Why This Matters

🌍 Real World

In blockchain, contract inheritance helps developers reuse code and build complex contracts efficiently, just like inheriting traits in real life.

💼 Career

Understanding contract inheritance is essential for blockchain developers to write clean, maintainable, and scalable smart contracts.

1

Create the base contract

Create a Solidity contract called ParentContract with a public string variable greeting set to "Hello from Parent".

Blockchain / Solidity

// Your code here

Need a hint?

Use contract ParentContract {} and declare string public greeting = "Hello from Parent"; inside.

2

Create the child contract with inheritance

Create a Solidity contract called ChildContract that inherits from ParentContract.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract ParentContract {
    string public greeting = "Hello from Parent";
}

// Your code here

Need a hint?

Use contract ChildContract is ParentContract {} to inherit.

3

Add a function to access inherited data

In ChildContract, add a public function called getGreeting that returns the greeting string from ParentContract.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract ParentContract {
    string public greeting = "Hello from Parent";
}

contract ChildContract is ParentContract {
    // Your code here
}

Need a hint?

Write a function getGreeting that returns greeting using return greeting;.

4

Display the inherited greeting

Write a line to print the result of calling getGreeting() from ChildContract. Use console.log style comment to simulate output since Solidity does not print directly.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract ParentContract {
    string public greeting = "Hello from Parent";
}

contract ChildContract is ParentContract {
    function getGreeting() public view returns (string memory) {
        return greeting;
    }
}

// Simulate calling getGreeting() and output the result
// Your code here

Need a hint?

Since Solidity contracts do not print directly, imagine calling getGreeting() returns "Hello from Parent".