Thread: Please see multiple questions I got wrong on an exam, what I did wrong?

Here is a list of what I had gotten wrong on an exam:

boolan a = false, b = true, c = true, d = false, e = true;

1. System.out.println a != c;

I had converted it to a==c, and had answered FALSE. I'm checking the answer again -- and since a = false, c = true; the result of a == c would be FALSE. FALSE was my answer.

But I got the answer wrong, did I read too much into it and convert the not equals into ==, when I should've left it alone, and resulting in a != c being TRUE. because that would be true, a(false) doesn't equal c(true.

2. This was a question that asked for showing the EXACT output that will be created by execution of the following program.

package javaapplication1;
 
 
public class JavaApplication1
{
 
    public static void main (String[] args) 
    {
        int manny = 40, moe = 23, jack = 26;
        System.out.printf ("%3d%3d%3d\n", manny, moe, ++jack);
            if (manny > moe)
                if (moe > jack) {
                        moe = 40;
                        System.out.printf ("%3d%3d\n", ++jack, moe--);
                    }
                else
                        manny-=manny;
            else
                if(moe > jack)
                        jack = 50;
                else
                    System.out.printf ("%3d%3d\n", ++jack, moe--);
          System.out.printf("%3d%3d%3d\n", manny, moe, ++jack);
           if (manny > moe)
               if (moe > jack)  {
                        moe = 31;
                        System.out.printf("%3d%3d\n", ++jack, moe--);
               }
           else
                        manny -= manny;
       else
           if(moe > jack)
                   jack = 50;
           else
               System.out.printf ("%3d%3d\n", ++jack, moe--);
       System.out.printf("%3d%3d%3d\n", manny, moe, ++jack);
    }
}

Here is how I tracked my variables, I would cross them out as I read through the program and the most bottom one would be the newest value
manny moe jack
40 23 26
0 22 27
28
29

My output looked like this(everything had to be exact, spacing is indicated by the underscore _ )
OUTPUT
_40_23_27
_28_23
__0_22_29


Please help me learn what I did wrong.

1. You're confusing me with your thought process, so I'm going to ignore it for a bit. This is what I see:

Given:
a = false, c = true

The statement:
a != c (say, "a does not equal c")

is TRUE, because (substitute from the givens):
false != true (say, "false does not equal true")

I don't have time now for #2, but I'll look at it later.

_40_23_27
__0_23_28
_29 23
__0_22_30

Originally Posted by ggx7

Please help me learn what I did wrong.

ggx7
It looks like you are evaluating statements that are made within an "else" that shouldn't be evaluated.
Eg
The first if statement

if (manny > moe)

is true, so you would never evaluate the "else" statement for that, even though by the time you get to that 'else' line, the original if statement would now be evaluated as false (because you aren't evaluating that if statement again, it was true when it was evaluated and that's all that matters, so skip the else).

Follow Kevin's advice and just compile this code and see what you get...