If-else statements in Blockchain / Solidity

Introduction

If-else statements help your program make choices. They let your code do different things depending on conditions.

Checking if a user has enough tokens to make a purchase.

Deciding if a transaction should be approved or rejected.

Verifying if a smart contract condition is met before executing.

Choosing different actions based on the current blockchain state.

Syntax

Blockchain / Solidity

if (condition) {
    // code to run if condition is true
} else {
    // code to run if condition is false
}

The condition is a check that results in true or false.

Use curly braces { } to group the code blocks clearly.

Examples

This checks if the balance is enough to buy something. If yes, it approves; if not, it rejects.

Blockchain / Solidity

if (balance >= price) {
    approvePurchase();
} else {
    rejectPurchase();
}

This checks if the user is the owner. Owners get access, others do not.

Blockchain / Solidity

if (isOwner) {
    allowAccess();
} else {
    denyAccess();
}

Sample Program

This smart contract checks if the balance is enough to buy an item. The buy function returns a message based on the check.

Blockchain / Solidity

pragma solidity ^0.8.0;

contract SimpleCheck {
    uint public balance = 100;
    uint public price = 50;

    function buy() public view returns (string memory) {
        if (balance >= price) {
            return "Purchase approved";
        } else {
            return "Purchase denied";
        }
    }
}

Important Notes

In blockchain smart contracts, if-else helps control what actions happen based on conditions.

Always test your conditions carefully to avoid unexpected results.

Summary

If-else lets your code choose between two paths.

Use it to check conditions and run different code accordingly.

It is very useful in blockchain for controlling transactions and permissions.