奇怪的JAVA布尔值评估问题

Question

Hi I have the following code:

  boolean result = someexpression();

            if(!result)
            {
            System.out.println("False..."); 
            }
            if (result); 
            {
                System.out.println("True");
            }

It prints both (False and true) I also tried using things like

     if(result==true)

but that doesnt seem to do the trick. No matter what the value of the variable it just enters the condition.?? I am using eclipse and this only happens at a specific portion.

Answer 1

if (result); 

Remove the ; at the end of this line.

With the ; , it means "if result is true , then do nothing". The block that contains the next statement isn't part of the if and will always be executed. It's exactly the same as this:

if (result)   // if result is true
    ;         // then do nothing

System.out.println("True");  // is always executed

Answer 2

You have a rogue semi-colon at the end of your if statement.

if (result);

This makes your code evaluate to

if (result) {

}
{
    System.out.println("True");
}

where the second pair of {} denotes a code block which always gets executed since it's not part of the if control block anymore. So get rid of that semi-colon (which I assume is not what you meant to put there)!