How to use this boolean in an if statement?

Question

private String getWhoozitYs(){
    StringBuffer sb = new StringBuffer();
    boolean stop = generator.nextBoolean();
    if(stop = true)
    {
        sb.append("y");
        getWhoozitYs();
    }
    return sb.toString();
}

This is a chunk of code for a project I'm doing in a programming course. The problem I'm having is that after declaring the boolean stop and trying to assign a randomly generated boolean value to it, I can't use it in the if statement to determine if I should append more y's to the StringBuffer or not. I do have the Random generator inside a constructor, so that part isn't a problem. I assumed that since I declared the boolean outside the if statement I would be able to use it inside, but that doesn't seem to be the case. The real question is how can I use a randomly determined boolean in an if statement.

Answer 1

if(stop = true) should be if(stop == true), or simply (better!) if(stop).

This is actually a good opportunity to see a reason to why always use if(something) if you want to see if it's true instead of writing if(something == true) (bad style!).

By doing stop = true then you are assigning true to stop and not comparing.

So why the code below the if statement executed?

See the JLS - 15.26. Assignment Operators:

At run time, the result of the assignment expression is the value of the variable after the assignment has occurred. The result of an assignment expression is not itself a variable.

So because you wrote stop = true, then you're satisfying the if condition.

Answer 2

if(stop == true)

or

if(stop)

= is for assignment.

== is for checking condition.

if(stop = true) 

It will assign true to stop and evaluates if(true). So it will always execute the code inside if because stop will always being assigned with true.