Enthuware

"Because the expression 'bool = false' returns a boolean ( which happens to be false)"
Is the above explanation correct for option number 4 for this question. Or, it does not have a compile and run time error because, after the assignment "bool=false" it gets evaluated to "if(bool)" and the value of bool is false at that point?

The explanation is correct. In Java, every assignment expression has a value, which is same as the value of the variable after the assignment has occurred. Therefore, the expression "bool = false" itself also has a value which happens to be same as the left hand side of the assignment i.e. the value of bool after assignment.

HTH,
Paul.

Are there other languages that would allow "if(x = 3)" to compile? Because I remember I once spent hours trying to figure out what was wrong with my code, and it ended up being a single equals sign inside an if statement.

I'm pretty sure it compiled, because if it hadn't, I would have seen the line number that caused the issue, and it wouldn't have taken hours.

And I'm pretty sure it wasn't a boolean because there's really no reason I would have attempted "bool == false" rather than just "!bool".

I just want to know if I'm misremembering the issue, or if it's entirely possible this was a problem and I'm just misremembering what language I was coding in at the time.

Any language that does not have a boolean data type will have this problem. For example, c uses int for a boolean (0 is false and any other value is true).
See this: https://stackoverflow.com/questions/146 ... nt-integer