If statements

[Joshua.Robinson]

I am working on a program that prompts the user to input 3 numbers and it evaluates the input and displays the numbers in nondecending order. My question is I have a couple lines of code that a classmate helped me write but he didn't offer me an explanation as to why this works, can anyone break it down for me?

if (val3 <= val1)
System.out.println(val3 + " " + val1 + " " + val2);

else if (val1 <= val3 && val3 <= val2)
System.out.println(val1 + " " + val3 + " " + val2);

else
System.out.println(val1 + " " + val2 + " " + val3);

here is my complete code:

import java.util.*;

public class Evaluate_3
{
static Scanner console = new Scanner(System.in);

public static void main(String[] args)
{

double val1, val2, val3;
double temp;

System.out.print("Enter three numbers with a space seperating each one: ");

val1 = console.nextDouble();
val2 = console.nextDouble();
val3 = console.nextDouble();

if (val1 > val2)
{
temp = val1;
val1 = val2;
val2 = val3;
}
System.out.printf("Your numbers in non decending order: ");

if (val3 <= val1)
System.out.println(val3 + " " + val1 + " " + val2);

else if (val1 <= val3 && val3 <= val2)
System.out.println(val1 + " " + val3 + " " + val2);

else
System.out.println(val1 + " " + val2 + " " + val3);
}
}

[Tolls]

Please use [code] tags [/code] when posting code, as that's almost unreadable without them.

Does that code actually work?

[Joshua.Robinson]

it does yes

[Tolls]

Does it work for val1 > val2?
Try it with the following numbers -> 10, 4, 8.

[Joshua.Robinson]

Ah good catch no it does not work, in that case it lists 4, 8, 8

[Tolls]

So this part needs correcting first:

if (val1 > val2)
{
   temp = val1;
   val1 = val2;
   val2 = val3;
}

[Joshua.Robinson]

Ok, that's kind of the part I was confused on, my counterpart didn't want to explain to me why he just wanted to write it and get it over with. I will read the section on if statements again in my textbook and post the result once it is corrected. Thank you for looking.

[JosAH]

Have a look at the Math.min( ... ) and Math.max( ... ) methods; also note that a+b+c-M-m (where M and m and the maximum and minimum of the three numbers a, b and c) results in the third 'middle' number.

kind regards,

Jos

[Joshua.Robinson]

I changed up everything, rewrote my if and else statements and I THINK I have got it so it is right (seems to work with any combination)

import java.util.Scanner;
 
 
public class Evaluate_3 {

public static void main(String[] args) 
{
Scanner input = new Scanner(System.in);
 
   System.out.print("Enter a number: ");

   double A = input.nextDouble();
   System.out.print("Enter a second number: ");

   double B = input.nextDouble();
   System.out.print("Enter a third number: ");

   double C = input.nextDouble();
   System.out.println("The numbers in non decending order are: ");

   displaySortedNumbers(A, B, C);

}
public static void displaySortedNumbers(double A, double B, double C) 
{

   if ( (A <= B) && (A <= C) ) 
   {
   System.out.print(A);

   if (B <= C)
   System.out.println(" " + B + " " + C);

   else
   System.out.println(" " + C + " " + B);
   }

   else if ( (B <= A) && (B <= C) ) {
   System.out.print(B);

   if (A < C)
   System.out.println(" " + A + " " + C);

   else
   System.out.println(" " + C + " " + A);
   }

   else if ( (C <= A) && (C <= B) ) {
   System.out.print(C);

   if (A < B)
   System.out.println(" " + A + " " + B);

   else
   System.out.println(" " + B + " " + A);
   }
}
}

[JosAH]

grmph ...

int max= Math.max(A, Math.max(B, C));
int min= Math.min(A, Math.min(B, C));
int mid= A+B+C-max-min;

kind regards,

Jos

[Tolls]

Depends if it's some sort of algorithm lesson.
The Math class might be considered cheating...:)