logic errors

Logic errors are mistakes in a program's reasoning that cause incorrect results even though the code runs without crashing.

Unlike syntax errors, which prevent execution, logic errors produce the wrong output: a calculation that's always off by one, a loop that runs forever, or a condition that triggers when it shouldn't.

The code compiled fine but gave wrong answers—must be a logic error.

These are often the hardest bugs to find because the computer does exactly what you told it to, not what you meant.