CODEWITHSUNDEEP
java
Lali
Lali

Reputation: 155

Why WHILE loop is stopped as soon as one condition is satisfied?

I'm writing class where I'm generating 2 random numbers a and b (between 1 to 100) and I want to keep generating those 2 numbers until a+b=20 and a*b=100 (both conditions must be true). when both conditions satisfied, I want to print a and b and also the numbers of tries it took to satisfy those conditions.

Here is my code

public class App {

    public static void main(String[] args) throws Exception {
        int a = 0;
        int b = 0;
        int add;
        int multi;

        int i=0;
        Random r = new Random();

        do{
            a = r.nextInt(99)+1;
            b = r.nextInt(99)+1;
            add = a+b;
            multi = a*b;
            i++;
            System.out.println("iteration number : " +i);
        }
        while(add != 20 && multi != 100);
        {
            System.out.println(a);
            System.out.println(b);

            System.out.println("Total Number of iteration: " +i);
        }
    }
}

here I'm getting output like

...
19
1
Total Number of iteration: 76

or

...
15
5
Total Number of iteration: 118

Why While loop is ending even only one condition is true and the other is not?

Upvotes: 1

Views: 490

Answers (2)

Kawser Habib
Kawser Habib

Reputation: 1422

Because your terminating condition is not correct.

Suppose, 
a = 17 and  b= 3,
Then, 
add = 20 and multi = 51, 
 
add != 20 (false) && multi != 100 (true) => false

So, when while gets false, it terminates the loop.

In other cases,

Suppose, 
a = 87 and  b= 38, 
add = 125 and multi = 3306,

add != 20 (true) && multi != 100 (true) => true

So, while does not break.

Your termination logic should be when both false only that time it will return false.

The way you can achieve this is:

add != 20 || multi != 100

Upvotes: 1

Md. Sajib Hosen
Md. Sajib Hosen

Reputation: 26

Maybe, You make mistakes on condition. it will be OR.

  do{
        a = r.nextInt(99)+1;
        b = r.nextInt(99)+1;
        add = a+b;
        multi = a*b;
        i++;
        System.out.println("iteration number : " +i);
    }
    while(add != 20 || multi != 100);

Upvotes: 0

Related Questions