If-else statements in Blockchain / Solidity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of an if-else statement?

An if-else statement lets a program choose between two paths: one if a condition is true, and another if it is false.

beginner

How do you write a simple if-else statement in Solidity?

You write it like this:<br>

if (condition) {<br>  // code if true<br>} else {<br>  // code if false<br>}

beginner

What happens if the if condition is false and there is no else block?

The program skips the if block and continues with the code after it, doing nothing inside the if.

intermediate

Can you have multiple conditions checked in an if-else structure?

Yes, by using else if blocks between if and else, you can check many conditions in order.

intermediate

Why are if-else statements important in blockchain smart contracts?

They let contracts make decisions, like checking if a user has enough balance before sending tokens.

What does an if-else statement do in a program?

A Chooses between two actions based on a condition

B Repeats code multiple times

C Stores data permanently

D Defines a new function

An if-else statement lets the program pick one action if a condition is true, and another if false.

In Solidity, what keyword starts the condition check?

A if

B for

C while

D switch

The keyword 'if' starts the condition check in Solidity and many other languages.

What happens if the if condition is false and there is no else block?

A The program crashes

B The if block runs anyway

C The program skips the if block and continues

D The else block runs

Without an else block, if the condition is false, the program just skips the if block.

How can you check multiple conditions in an if-else structure?

A Using multiple if statements only

B Using else if blocks

C Using switch-case only

D Using loops

You use else if blocks to check multiple conditions in order.

Why are if-else statements useful in smart contracts?

A To store user data

B To connect to the internet

C To create new tokens

D To make decisions based on conditions

If-else statements let smart contracts decide what to do based on conditions like balances or permissions.

Explain how an if-else statement controls the flow of a program.

Think about choosing between two roads based on a sign.

Describe a real-life example where an if-else statement would be useful in a blockchain smart contract.

Imagine sending money only if you have enough.