Help with Program . . .

First Off . . . Im not looking for anyone to write the code for me. That being said I need some pointers on what I'm doing wrong with my program.

Program Description: Should have a "while" loop that asks repeatedly for a number until a number divisible by 3 or 7 is given. When that occurs, your program should display the number of numbers read.

Here is what I have thus far :

Quote:

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import java.util.Scanner;
public class DivisibleBy3or7
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println("This program reads numbers until one is divisible by 3 or 7");
System.out.println("Write a Number: ");
int Number = input.nextInt();
int i = 1;
int sum = 0;
while (( Number % 3 != 0 ) && ( Number % 7 != 0 ))
{
sum = sum + 1
System.out.println("Write a Number; ");
i++;
}
System.out.println("There were " + sum + " numbers read ");
}
}

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There is something misplaced or left out. . . Im new to programming and haven't figured out to get what's in my head translated to the computer.

Thanks,

Dan

What does your program do? Does it work? Does it have errors?

Quote:

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"while" loop that asks repeatedly

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I don't see any asking being done in the while loop.

I'm sorry. . It doesn't work. . .it just prints the first two lines. . then when I enter a number it does a continuous print of "Write a Number".

Im sure my error is with my while loop. Im not to sure how to get it to ask "Write a Number" one time at a time.

Quote:

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I don't see any asking being done in the while loop.

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Your not asking inside the loop. How will Number ever change?

Code:

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import java.util.Scanner;
public class Divisibleby3or7
{
        int number=0;
        public Divisibleby3or7(){
                Scanner input = new Scanner(System.in);
                int sum = 0;
                do
                {
                        sum = sum + 1;       
                        System.out.println("This program reads numbers until one is divisible by 3 or 7");
                        System.out.println("Write a Number: ");
                        number = input.nextInt();
                       
                }while(( number % 3 != 0 )||( number % 7 != 0 ));
               
                System.out.println("There were " + sum + " numbers read ");
        }
        public static void main(String[] args)
        {
                new Divisibleby3or7();
        }
}

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Quote:

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Originally Posted by DSutta22

First Off . . . Im not looking for anyone to write the code for me.

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You are much clever pal. Really nice to see your attempt here that make to learn Java. Keep going.

Regrading your code, first thing is you misses a semicolon at the end of following line, within the while loop.

Code:

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sum = sum + 1

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Now look at the code from the beginning. Using a scanner object you collect an int number, say 4. Then you entered to the while loop and do the validation. According to your validation while loop return true. So you can entered to the while loop. There you have three lines.

Code:

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[LIST=1][*]while (( Number % 3 != 0 ) && ( Number % 7 != 0 )) {[*]sum = sum + 1;[*]System.out.println("Write a Number; ");[*]i++;[*]}[/LIST]

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Second line of the while loop, increment the value of sum by 1. Third line just display a line of text to the console. On line four you do another increment as well.

So is there any process taken to exit from the while loop? NO, so you have endless loop. Until you exit the application, it prints a line of text to the console.

What you have to do is, use a do-while loop. In do-while loop before the condition is check it guaranteed that body of the loop execute at least once.

But the following line is never executed.

Code:

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}while(( number % 3 != 0 )||( number % 7 != 0 ));

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Think about that, what exactly happen.

oh shit i made a little mistake with condition in while,it was too late at night,that i wrote the code,lol,but i think he understood the idea with do-while loop

Quote:

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Originally Posted by serjant

oh shit i made a little mistake with condition in while,it was too late at night,that i wrote the code,lol,but i think he understood the idea with do-while loop

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Yes pal, I know that you are not tested this code and write on the forum directly. Don't worry, I hope our thread starter find what happen there. Actually it's really nice point to think for him. :)