Need help retrieving largest index from array

Question

I'm stuck... My code was working earlier, but now it just hangs. On top of that I can't seem to get my getHighest and getSmallest methods to return the correct values. I don't know if I'm just not catching something. Any help would be great!

import java.util.Scanner;
import java.text.DecimalFormat;
public class Rainfall
{
 public static void main(String[] args)
 {
 final int MONTHS = 12;
 double[] rain = new double[MONTHS];
 initRain(rain);
 double total = totalRain(rain);
 double average = averageRain(rain, total);
 double most = mostRain(rain);
 double least = leastRain(rain);
 DecimalFormat digit = new DecimalFormat("#.0");
 System.out.println("The total rainfall of the year is " + digit.format(total));
 System.out.println("The average rainfall of the year is " + digit.format(average));
 System.out.println("The month with the highest amount of rain is " + most);
 System.out.println("The month with the lowest amount of rain is " + least);
 }
 public static void initRain(double[] array)
 {
 Scanner keyboard = new Scanner(System.in);
 for (int x = 0; x < array.length; x++)
 { 
 System.out.print("Enter Rainfall for month " + (x + 1) + ": ");
 array[x] = keyboard.nextDouble();
 }
 }
 public static double totalRain(double[] array)
 {
 double total = 0;
 for (int x = 0; x < 12; x++)
 total += array[x];
 return total;
 }
 public static double averageRain(double[] array, double total)
 {
 return total / array.length;
 }
 public static double mostRain(double[] array)
 {;
 double maximum = array[1];
 int value = 0;
 for (int i=0; i < 12; i = i++)
 {
 if (array[i] >= maximum)
 maximum = array[i];
 value = i;
 }
 return value;
 }
 public static double leastRain(double[] array)
 {
 double minimum = array[0];
 int value;
 for (int i=0; i < 12; i++)
 {
 if (array[i] <= minimum) 
 minimum = array[i];
 value = i;
 }
 return value;
 }
}

• le3th4x0rbot: In the leastRain() and mostRain() methods you are returning value in the for loop, but you should actually return it after the loop...
• le3th4x0rbot: Also, when iterating over arrays, it is pretty much never ever a good idea to hard code the length into a for loop... even if you dont think it will ever change. Always use array.length, or at least a variable that you can quickly change later if the array length changes. for (int i=0; i < array.length ; i++)
• jreed1: Ahhh thank you! that did help, can you explain why code is just hangin right now though :( I greatly appreciate it!
• pillingworth: You've also got an interesting i = i++ in the mostRain(...) for loop. That's your problem. You are setting i to the value of i before it is incremented. So in effect not incrementing i.
• le3th4x0rbot: I am not really sure what you mean by hanging. You mean it is running, but not producing any discernible result? Is it throwing an exception?

Answer 1

Your program hangs because of this line:

for (int i=0; i < 12; i = i++)

The problem is that i++ returns the value of i before the variable is incremented, so the increment step of your loop is the same as writing i=i. Thus, the variable i never reaches the escape condition of the loop.

it should be:

for (int i=0; i < 12; i++)

Cleaned up your code a little bit, can be improved a lot. There were many simple errors.

import java.util.Scanner;
import java.text.DecimalFormat;
public class Rainfall
{
 public static void main(String[] args)
 {
 final int MONTHS = 12;
 double[] rain = new double[MONTHS];
 initRain(rain);
 double total = totalRain(rain);
 double average = averageRain(rain, total);
 int most = mostRain(rain);
 int least = leastRain(rain);
 DecimalFormat digit = new DecimalFormat("#.0");
 System.out.println("The total rainfall of the year is " + digit.format(total));
 System.out.println("The average rainfall of the year is " + digit.format(average));
 System.out.println("The month with the highest amount of rain is " + (most + 1));
 System.out.println("The month with the lowest amount of rain is " + (least + 1));
 }
 public static void initRain(double[] array)
 {
 Scanner keyboard = new Scanner(System.in);
 for (int x = 0; x < array.length; x++)
 {
 System.out.print("Enter Rainfall for month " + (x + 1) + ": ");
 array[x] = keyboard.nextDouble();
 }
 }
 public static double totalRain(double[] array)
 {
 double total = 0;
 for (int x = 0; x < 12; x++)
 total += array[x];
 return total;
 }
 public static double averageRain(double[] array, double total)
 {
 return total / array.length;
 }
 public static int mostRain(double[] array)
 {
 double maximum = array[1];
 int value = 0;
 for (int i=0; i < 12; i++) {
 if (array[i] >= maximum) {
 maximum = array[i];
 value = i;
 }
 }
 return value;
 }
 public static int leastRain(double[] array)
 {
 double minimum = array[0];
 int value = 0;
 for (int i=0; i < 12; i++)
 {
 if (array[i] <= minimum) {
 minimum = array[i];
 value = i;
 }
 }
 return value;
 }
}