In Solidity, what is the difference between using if() and require()?

Question

I can run code inside a conditional if statement. I can also require a condition before running some code. Are they interchangeable or are there reasons I would choose to rely on one and not the other?

Answer 1

No, they are different and not interchangeable.

When an ifcondition is false, the next condition/block is executed and the else block (if any) is run. Standard if/else programming logic.

require is an error-handling statement. When a required condition is false, all execution stops and the transaction is rolled back.