Boolean expression which controls the if statement in java

Question

class ee
{
    public static void main(String args[])
    {
        boolean a;
        a=true;
        System.out.println("Answer is "+a);
        a=false;
        System.out.println("Answer is "+a);
        if(a) System.out.println("This is not executed");
        a=true;
        if(a)
        System.out.println("This is executed");
        System.out.println("10>11 is "+(10>11));
    }
}

Output:

Ansewr is true Answer is false This is executed 10>11 is false

Why it is showing "This is executed" in the third line of the output? Why "This is not executed" is not there in the output ?

You have to read some documentation about [`if` statement](http://www.tutorialspoint.com/java/if_else_statement_in_java.htm) — tfosra, Jun 15 '16 at 10:10
I think you should use brackets with your `if`s to avoid errors in the corresponding block of statements. — Kit Ostrihon, Jun 16 '16 at 11:09

score 1 · Answer 1 · answered Jun 15 '16 at 10:19

Let's look each line of the code.

class ee
{
    public static void main(String args[])
    {
        boolean a;

        a=true;
        System.out.println("Answer is " + a);  // OUTPUT Answer is true

        a=false;
        System.out.println("Answer is " + a);  // OUTPUT Answer is false

        //You are basically saying that if the statement is true, do this part(Inside the curly brackets)
        // a = false here so the program will not do inside the curly brackets
        if(a)
        {
            System.out.println("This is not executed");
        }

        a=true;

        // a = true here so the program will do inside the curly brackets
        if(a)
        {
            System.out.println("This is executed");
        }

        System.out.println("10>11 is "+(10>11));
    }
}

I guess you know about if statements, but If you want to learn more about using if statements go here

score 0 · Answer 2 · answered Jun 15 '16 at 09:58

0

Because a is false in the first if, and true in the second. The statement inside the if sentence is executed only if the if's condition is true

answered Jun 15 '16 at 09:58

SCouto

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score 0 · Answer 3 · answered Jun 15 '16 at 10:01

         a=false;
        System.out.println("Answer is "+a);
        if(a) System.out.println("This is not executed");
        a=true;
        if(a)
        System.out.println("This is executed");

If you look at your code, you are setting a to false, if(a) by default assumes a is true, so it does not show "This is not executed". You are again setting a to true, so here it now shows "This is executed".

score 0 · Answer 4 · answered Jun 15 '16 at 10:15

I hope it would help you, go through each comments properly,

boolean a;  //default value false
                a=true; //assinged 'a' to true
                System.out.println("Answer is "+a); //so it prints true here
                a=false;   //again assigned it to false
                System.out.println("Answer is "+a);  // so it prints as false here
                if(a) System.out.println("This is not executed");
        /*
        the above line means as if(a){// a is false here, then it wont go inside, HENCE IT IS NOT THERE IN OUTPUT
        System.out.println("This is not executed");
        }

        */
                a=true; // again a assigned as true
                if(a)
                System.out.println("This is executed");
    /*
        the above line means as if(a){// a is true here, then it goes inside, HENCE IT IS THERE IN OUTPUT
        System.out.println("This is executed");
        }

        */

score 0 · Answer 5 · answered Jun 15 '16 at 10:16

    a=false;
    System.out.println("Answer is "+a);
    if(a) System.out.println("This is not executed");
    a=true;
    if(a)
    System.out.println("This is executed");
    System.out.println("10>11 is "+(10>11));

The a = false changes a to false and hence if(a) System.out.println("This is not executed"); is not executed then passing a=true; makes a true and thats why System.out.println("This is executed"); bgot executed

Boolean expression which controls the if statement in java

5 Answers5