Assistance with code

[Jeff Boynton]

Hi Everyone,

I am writing a program that is supposed to take 3 numbers inputted by the user and sorting them out in an ascending order. I believe my code is correct but can't figure out why the program isn't behaving as expected.

import java.util.*; //Required to use the scanner console

public class Week3_Programming_Problem
{
   static Scanner console = new Scanner(System.in); //Allows for user input
   
   public static void main(String[] args)
   {
   
   int num1; // Initialize variable
   int num2; // Initialize variable
   int num3; // Initialize variable
   
   System.out.println("Please enter a whole number: "); // Prompts user for input
   num1 = console.nextInt(); // Assigns input from user to variable
   
   System.out.println("Please enter a second whole number: "); // Prompts user for input
   num2 = console.nextInt(); // Assigns input from user to variable
   
   System.out.println("Please enter a third whole number: "); // Prompts user for input
   num3 = console.nextInt(); // Assigns input from user to variable
   
   if ((num1 < num2) && (num2 < num3)) // Beginning of nested if statements. Analyze numbers and sort in ascending order
      System.out.println("The numbers sorted in an ascending order are: " + num1 + " " + num2 + " " + num3); // Print numbers
   else if ((num1 < num2) && (num2 > num3))
      System.out.println("The numbers sorted in an ascending order are: " + num1 + " " + num3 + " " + num2);
   else if ((num1 > num2) && (num2 > num3))
      System.out.println("The numbers sorted in an ascending order are: " + num3 + " " + num2 + " " + num1);
   else if ((num1 > num2) && (num2 < num3))
      System.out.println("The numbers sorted in an ascending order are: " + num2 + " " + num1 + " " + num3);
   else if ((num2 > num3) && (num2 < num1))
      System.out.println("The numbers sorted in an ascending order are: " + num3 + " " + num1 + " " + num2);
   else 
      System.out.println("The numbers sorted in an ascending order are: " + num2 + " " + num3 + " " + num1);
      
   }
   
}

Any pointers would be really appreciated!

[Paul Clapham]

Welcome to the Ranch, Jeff!

So... how is the program behaving, then? What does it do which you didn't expect? Does it throw exceptions? Produce incorrect output? Have a look at our FAQ entry TellTheDetails (<== click that link) to see what kind of information is helpful for people trying to answer questions.

[Jeff Boynton]

It seems to work great up until the final "else if" statement. For instance, when I input 2 3 1 for numbers it comes back with 2 1 3. Forgive me for not knowing this. I am still really new to this!

[Paul Clapham]

Well, have a look at these two lines of code:

   else if ((num1 < num2) && (num2 > num3))  
      System.out.println("The numbers sorted in an ascending order are: " + num1 + " " + num3 + " " + num2);  

The output from the second line suggests that you know that num1 is less than num3. But your test in the first line doesn't tell you that. For example the three numbers could be 3, 6, and 1. Now look at these two lines:

   if ((num1 < num2) && (num2 < num3)) // Beginning of nested if statements. Analyze numbers and sort in ascending order  
      System.out.println("The numbers sorted in an ascending order are: " + num1 + " " + num2 + " " + num3);

These two lines are good because the test you do matches the output you produce exactly. So I would change your code so all six comparisons work the same as this one.

[Liutauras Vilda]

Try to use arrays (read about it) for such a problems like this, when you need to store more than one input of the same type data.

import java.util.Scanner;

public class Array {

public static void main(String[] args) {

Scanner in = new Scanner(System.in);

// create an array of 3 elements
int[] array = new int[3];

// ask user input
System.out.println("Enter three numbers followed by space: ");

// store user's inputs in an array
for (int i = 0; i < 3; i++) {

array[i] = in.nextInt();
}

/*
* Over here, try to think and figure it out, how to sort these array elements.
* Each array element can be accessed by indexes.
* For ex. array[0] - 1st element in an array
* array [1] - 2nd
* array [2] - third element in array and it is your last element.
* As they start from index 0, 1, 2 << 3 (...new int[3])
*/


// print elements of array
for (int i = 0; i < 3; i++) {

System.out.println(array[i]);
}

in.close();
}
}

[Jeff Boynton]

That did it! Here is my final code. Everything works great! Thank you so much for the help.

import java.util.*; //Required to use the scanner console

public class Week3_Programming_Problem
{
   static Scanner console = new Scanner(System.in); //Allows for user input
   
   public static void main(String[] args)
   {
   
   int num1; // Initialize variable
   int num2; // Initialize variable
   int num3; // Initialize variable
   
   System.out.println("Please enter a whole number: "); // Prompts user for input
   num1 = console.nextInt(); // Assigns input from user to variable
   
   System.out.println("Please enter a second whole number: "); // Prompts user for input
   num2 = console.nextInt(); // Assigns input from user to variable
   
   System.out.println("Please enter a third whole number: "); // Prompts user for input
   num3 = console.nextInt(); // Assigns input from user to variable
   
   if ((num1 < num2) && (num2 < num3)) // Beginning of nested if statements. Analyze numbers and sort in ascending order
      System.out.println("The numbers sorted in an ascending order are: " + num1 + " " + num2 + " " + num3); // Print numbers
   else if ((num1 < num3) && (num3 < num2))
      System.out.println("The numbers sorted in an ascending order are: " + num1 + " " + num3 + " " + num2);
   else if ((num3 < num2) && (num2 < num1))
      System.out.println("The numbers sorted in an ascending order are: " + num3 + " " + num2 + " " + num1);
   else if ((num2 < num1) && (num1 < num3))
      System.out.println("The numbers sorted in an ascending order are: " + num2 + " " + num1 + " " + num3);
   else if ((num3 < num1) && (num1 < num2))
      System.out.println("The numbers sorted in an ascending order are: " + num3 + " " + num1 + " " + num2);
   else 
      System.out.println("The numbers sorted in an ascending order are: " + num2 + " " + num3 + " " + num1);
      
   }
   
}

[Junilu Lacar]

!!! !!!

Ok, I understand that this is just Week 3 and you're probably in the early part of a learning progression. Hopefully, this is exercise just expects you to get a handle on how relational and boolean operations work. However, this is certainly not a good way to "sort" things with a computer program.

[Jeff Boynton]

I am sure that there are much easier ways to do this, and yes you are correct this is week 3 of a course I am taking and the topic is boolean operators and how they work.

[Jeff Boynton]

Out of curiosity, what would be the easier way to code this? Would an array be easier?

[Junilu Lacar]

Yes, the usual approach is to have a container of some sort, like an array, to hold the items you want to sort. Then you would apply an algorithm to sort your collection of things and the algorithm usually involves a loop. A loop is a program execution flow control structure that repeats a set of instructions for a finite number of times. Each execution of the instructions in a loop is called an iteration. You'll learn all this eventually. If you're really curious, check out the Java Tutorials

[Jeff Boynton]

Thank you for the info! You all have been very helpful. I'm going to browse the site to familiarize myself a little more with what I have in store for me in the coming weeks.