See the return value in the return statement - java

Question

There is a statement like this

double pow(double num, int exp){
    if(exp < 0)
        return (1/power2(num, -exp));
    else
        return power2(num,exp);
}

I want to view the value returned by power2(num,exp) function in the debugger window, without having to store the returned value in an intermediate variable. How is this done?

You won't be able to directly. You can use the expression evaluator by copying and executing the same code that appears in the return statement. — Sotirios Delimanolis, Jul 08 '15 at 19:11

M A · Answer 1 · 2015-07-08T19:25:09.827

2

In the Eclipse debug perspective, open the Display view and write the expression that calls the method. You can then evaluate it by selecting it and pressing the key combination (on Windows) Ctrl+Shift+I.

Of if you want to "watch" the value of the expression, you can use the Expressions view instead.

Note that this will actually run the code behind the method. So make sure you invoke expressions that don't affect the execution flow of your program while debugging. If you want to minimize side effects, it's better to just write a reduced expression. For example, instead of evaluating the whole method invocation, which could do side effects in its body, you can evaluate just the temporary expression you want to watch.

edited Jul 08 '15 at 19:25

answered Jul 08 '15 at 19:12

M A

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Careful with side effects. – Sotirios Delimanolis Jul 08 '15 at 19:13
@SotiriosDelimanolis you told him to do the same thing...? – brso05 Jul 08 '15 at 19:13
@brso05 There is a subtle difference between my answer and Sotirios' comment. Here I'm suggesting to evaluate the method invocation. His comment was to evaluate just the expression in the return statement. – M A Jul 08 '15 at 19:30
@manouti true but the expression in the return statement could have bad side effects also depending on what is in that expression... – brso05 Jul 08 '15 at 19:33
Thank you all for your valuable comments – Twin Jul 09 '15 at 13:55

See the return value in the return statement - java

1 Answers1