Java nested while loops

Question

I need nested while loops to print so that the outter loop k makes one decrement iteration every time that inner loop "I" finishes an iteration. K has to start at 5 and count back to 1 and I has to starts at 0 and count to 10 by 2's. So it would the out put would look like this:

K = 5 I = 0
K = 5 I = 2
K = 5 I = 4
K = 5 I = 6
K = 5 I = 8
K = 5 I = 10
K = 4 I = 0

I have been stumped for hours and tried everyway to I can think of to make it work. Can someone please help?

public class Task1 {
public static int i = 0;
public static int k = 5;

public static void Display(){

    while(k > 1){

        while(i >=10){
            i = i+2;
            System.out.println("K = " + k + " I = " + i);

        }


        if (i >= 10){
            k=k-1;
        }
    }
}


public static void main(String[] args) {
    // TODO Auto-generated method stub
    Display();

}
    }

Why use while loops? This is normally done as for( int i = 5; i > 0; i-- ) for( int j = 0; j <= 10; j = j+2 ) System.our.println( i + " " + j); of course making same with whole loops is trivial if you have seen that a for loop is very much like a while loop. — simbo1905
– simbo1905, Commented Mar 14, 2015 at 20:26

Bhargav Rao · Accepted Answer · 2015-03-14 20:37:15Z

3

There are a few errors. Follow the comments

while(k >= 1){                                        // Make it >= instead of >

    i = 0;                                            // reset i
    while(i <=10){                                    // Make it i<= (less than)
        System.out.println("K = " + k + " I = " + i); //print before incrementing
        i = i+2;

    }

Rest of the code is correct. And the output is as expected

K = 5 I = 0
K = 5 I = 2
K = 5 I = 4
K = 5 I = 6
K = 5 I = 8
K = 5 I = 10
K = 4 I = 0
K = 4 I = 2
K = 4 I = 4
K = 4 I = 6
.
.
.

edited Mar 14, 2015 at 20:37

answered Mar 14, 2015 at 20:21

Bhargav Rao

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3 Comments

user2796618 Over a year ago

this works but for some reason k is stopping before it goes to 1 and prints the last iteration. any idea why? thanks for all of the help

Bhargav Rao Over a year ago

@user2796618 Just make it >= in the while loop. Check the edit

user2796618 Over a year ago

nevermind I figured it out. I needed an = in the first while thanks for helping everyone

Scott Hunter · Accepted Answer · 2015-03-14 20:18:37Z

1

You need to initialize i before the start of the inner loop, inside the outer loop, so it gets reset each time

answered Mar 14, 2015 at 20:18

Scott Hunter

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2 Comments

user2796618 Over a year ago

Now my out put looks like this : K = 5 I = 2 K = 5 I = 4 K = 5 I = 6 K = 5 I = 8 K = 5 I = 10 K = 4 I = 12 K = 3 I = 2 K = 3 I = 4 K = 3 I = 6 K = 3 I = 8 K = 3 I = 10 K = 2 I = 12

Scott Hunter Over a year ago

Note that every I printed is 2 too big; I'll leave fixing that as an exercise.

Ryan Smith · Accepted Answer · 2015-03-14 20:26:50Z

0

while(k > 1) {
   i = 0;
   while( i <= 10) { 
     Print
      i += 2;
   }
   k--;
 }

Your inner while loop condition was incorrect. And you were adding to i too soon so you would never print for 0.

edited Mar 14, 2015 at 20:26

answered Mar 14, 2015 at 20:20

Ryan Smith

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Comments

Bhargav Rao · Accepted Answer · 2015-03-14 20:27:09Z

0

Something like this

public class Task1 {
public static int i = 0;
public static int k = 5;

public static void Display(){

    while(k > 0){
        i = 0;
        while(i <= 10){
            System.out.println("K = " + k + " I = " + i);
            i+=2;
        }
        k--;

    }
}

public static void main(String[] args) {
    Display();

}
}

edited Mar 14, 2015 at 20:27

Bhargav Rao

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answered Mar 14, 2015 at 20:21

Vladislav Lezhnin

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1 Comment

Ryan Smith Over a year ago

Your inner while loop should be less than or equal to.

SKDroid · Accepted Answer · 2015-03-14 20:34:59Z

0

Replace your display method with this..

public static void Display(){

       while(k > 1){
          i=0; //initialise i back to 0
          while(i <=10){ //Change >= to <=
               i = i+2;
               System.out.println("K = " + k + " I = " + i);
          }
         k--;
        //comment or delete below if block
        /*if (i >= 10){
           k=k-1;
        }*/
    }
 }

answered Mar 14, 2015 at 20:34

SKDroid

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Comments

DnwAlgorithma · Accepted Answer · 2015-03-14 20:47:56Z

0

use the following code.

public class Task1 {

public static int i = 0;
public static int k = 5;

public static void Display() {

    while (k >= 1) { // use >=1 if you wanna print till 1
        i = 0; // set i=0
        while (i <= 10) {
            System.out.println("K = " + k + " I = " + i); // add print
                                                            // statement
            i = i + 2;

        }
        k--; // no need to use if (i >= 10){ }

    }
}

public static void main(String[] args) {
    // TODO Auto-generated method stub
    Display();

}

}

answered Mar 14, 2015 at 20:47

DnwAlgorithma

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Comments

Ski · Accepted Answer · 2015-03-14 20:23:41Z

-1

You can do it like this:

for(int k = 5;k>0;k--;){
for(int i = 0;i<10;i+=2;)
 System.out.println(k+ "" +i)
}

answered Mar 14, 2015 at 20:23

Ski

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