Not quite understanding the do while loop.

Question

Instructions from the teacher - Using a do-while loop, multiply the given number variable by two until its value is over 1 million. In each iteration of the loop, after you multiply the number variable.

Here's my code:

import java.util.Scanner;

class Main {

static Scanner userInput = new Scanner(System.in);

public static void main(String[] args) {
int testNumber = userInput.nextInt();
// Write your code below here
do {
System.out.println(testNumber*2);
testNumber++;
} while(testNumber == 1000000);

}
}

My output is 10. I like this but how do I get it to loop through and times them all by 2 each loop?

Thanks.

Answer 1

do while first evaluate and then check the condition. it means loop can run at least one time .change the condition
while(testNumber<1000000)
I think it can help you , if no let me know ...

Answer 2

It probably times out because you want it to count to 1 million and print a million lines of output. If you reduce it to while(... <= 500) it should work better

Answer 3

Thanks, Shruti. When I do that I get no output at all.

Answer 4

Ah! Thank you, Gordie! It worked!

Answer 5

multiply the orginal line of code by 2

Answer 6

if you don't want to print every no. ....
try this:
do{
int s =testnumber*=2;
}while(testnmber<1000000);
System.out.println(s);

Answer 7

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the do while statement really helps when youre trying to increment something. my example i'snt written in actual code but it gives you an idea of whats happening:

var: numberOfApples
NumberOfApples=0

do{
inc. NumberOfApples
}
while NumberOfApples<10

hope this helped😎

zach

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