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Java

Posted by Kevin Ley
Kevin Ley
1,402 Points

please help with this beginner loop program for java

My code runs but I cannot get the sum of the numbers I input once the program runs. I am a beginner so if I can get help with this it would help me gain knowledge on how loops really work. THANK YOU public class SumOfNumbers { private int mNumber;

public SumOfNumbers(int number){
    mNumber = number;
}

public void setNumber(int number) {
    mNumber = number;
}

public int getNumber() {
    return mNumber;
}

public int sumOfNumbers() {
    int sum = 0;    
    do {
        getNumber();
        if(getNumber() < 0) {
            break;
        }
        sum += getNumber();
    } while (true);
    return sum;

}

public String toString() {
    String str = "Sum of numbers is :" +sumOfNumbers();
    return str;
}

}

import java.util.Scanner; public class SumOfNumbersDemo {

public static void main(String[] args) {
    int number = 0;
    SumOfNumbers sum = new SumOfNumbers(number);
    Scanner scan = new Scanner(System.in);
    System.out.println("This Program will collect numbers and add them up. ");
    System.out.println("Enter a nonzero integer. To stop input negative value:  ");
    sum.setNumber(scan.nextInt());
    sum.sumOfNumbers();
    System.out.print(sum.sumOfNumbers());
}

}

1 Answer

jcorum
jcorum
71,830 Points

To get things started, let's do something a bit simpler. We will still add up some numbers, but all in one program:

import java.util.Scanner; 

public class SumOfNumbersDemo {

   public static void main(String[] args) {
       //create a Scanner object
       Scanner scan = new Scanner(System.in);
       //put a prompt to the user on the console
       System.out.println("This Program will collect numbers and add them up. ");
       System.out.println("Enter a nonzero integer. ");
       //get the user's input, using the Scanner object scan
       int limit = scan.nextInt();
       //call the sumOfNumbers() method with the user's limit number, and print out the returned value
       System.out.println(sumOfNumbers(limit));
   }

   //method that takes one parameter, a limit number
   public static int sumOfNumbers(int limit) { 
       //initialize a variable to hold the sum
      int sum = 0;
       //loop through the integers from 0 to the number the user entered
      for (int i = 0; i <= limit; i++) {
         //add up the numbers - this is shorthand for sum = sum + i
         sum += i;
      }
      return sum;
   }
}

If you put this in a file named SumOfNumbersDemo, it will compile and run. It will ask the user for a number, and then it will print the sum of the numbers from 0 to that number, inclusive. It doesn't check to see if the user actually enters a number, or if that number is positive. So it needs a bit of work. But it's a start. Later, after you get this going, the next step would be to see if there's any need to create a class, like your SumOfNumbers, to replace the method.

Kevin Ley
Kevin Ley
1,402 Points

thank you so much!!!!!