Function overloading in Blockchain / Solidity - Mini Project: Build & Apply

Function overloading in Solidity

📖 Scenario: You are building a smart contract for a simple calculator on the Ethereum blockchain. You want to create a contract that can add numbers in different ways using the same function name but with different inputs.

🎯 Goal: Build a Solidity contract that demonstrates function overloading by creating multiple add functions with different parameters.

📋 What You'll Learn

Create a contract named Calculator

Create an add function that takes two uint numbers and returns their sum

Create an overloaded add function that takes three uint numbers and returns their sum

Create an overloaded add function that takes two int numbers and returns their sum

💡 Why This Matters

🌍 Real World

Function overloading is useful in smart contracts to provide flexible interfaces for users, allowing the same function name to handle different input types or numbers.

💼 Career

Understanding function overloading is important for blockchain developers to write clean, reusable, and user-friendly smart contracts.

1

Create the Calculator contract with the first add function

Create a Solidity contract named Calculator. Inside it, write a public function called add that takes two uint parameters named a and b, and returns their sum as uint.

Blockchain / Solidity

contract Calculator {
    // Your code here
}

Need a hint?

Remember to declare the contract with contract Calculator { } and the function with the exact name add and parameters uint a, uint b.

2

Add an overloaded add function with three uint parameters

Inside the Calculator contract, add another public function named add that takes three uint parameters named a, b, and c, and returns their sum as uint.

Blockchain / Solidity

contract Calculator {
    function add(uint a, uint b) public pure returns (uint) {
        return a + b;
    }

    // Your code here
}

Need a hint?

Use the same function name add but with three uint parameters to overload the function.

3

Add an overloaded add function with two int parameters

Inside the Calculator contract, add another public function named add that takes two int parameters named a and b, and returns their sum as int.

Blockchain / Solidity

contract Calculator {
    function add(uint a, uint b) public pure returns (uint) {
        return a + b;
    }

    function add(uint a, uint b, uint c) public pure returns (uint) {
        return a + b + c;
    }

    // Your code here
}

Need a hint?

Overload the add function again but this time use int parameters instead of uint.

4

Test the add functions by calling them

Add a public function named testAdd that calls each add function with example values and returns the sum of all results as uint. Use add(2, 3), add(1, 2, 3), and add(int(-1), int(4)). Convert the last int result to uint by casting. Then return the total sum.

Blockchain / Solidity

contract Calculator {
    function add(uint a, uint b) public pure returns (uint) {
        return a + b;
    }

    function add(uint a, uint b, uint c) public pure returns (uint) {
        return a + b + c;
    }

    function add(int a, int b) public pure returns (int) {
        return a + b;
    }

    // Your code here
}

Need a hint?

Call each add function with the exact values and add their results. Cast the int result to uint before adding.