CODEWITHSUNDEEP
javaarrays
Christian Lapinig
Christian Lapinig

Reputation: 43

Java - Finding Largest and Smallest Numbers using an Array

I am supposed to make a program that takes 10 numbers from a user input, find the largest and smallest number and display all the inputs from the user. This program does use an array. Here is my code:

import java.util.Scanner; // program uses Scanner
public class ArrayTester {
    // begin execution
    public static void main(String[] args) {
        // declare and create array object
        // declare smallest and largest int variables 
        int[] numbers;
        numbers = new int[10];
        int smallest = numbers[0], largest = numbers[0];

        // create Scanner object
        Scanner input = new Scanner(System.in);

        // prompt user 
        System.out.print("Please enter 10 numbers: \n");
        // use for loop to obtain user input
        for (int counter = 0; counter < numbers.length; counter++) {
            numbers[counter] = input.nextInt();
        } // end obtaining input

        // enhanced for loop to find largest and smallest values
        for (int i : numbers) {
            if (numbers[i] < smallest) {
                smallest = numbers[i];
            } // end finding smallest
            else if (numbers[i] > largest) {
                largest = numbers[i];
            } // end finding largest number 
        } // end finding largest and smallest values

        // for loop to print user input 
        System.out.printf("%s%8s\n", "Index", "Input");
        for (int counter = 0; counter <= numbers.length; counter++) {
            System.out.printf("%5d%8d\n", counter, numbers[counter]);
        } // end printing input values

        // print smallest and largest numbers
        System.out.printf("Smallest number: %d\nLargest number: %d\n", smallest, largest);
        System.out.print("Programmed by Christian Lapinig");
    } // end main
 } // end ArrayTester

At this point I am able to obtain user inputs, but I run into this problem:

Please enter 10 numbers: 
454
392
33
41
6
44
39
21
12
2
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 454
at ArrayTester.main(ArrayTester.java:32)

Would I need a try and catch block to fix this?

Upvotes: 3

Views: 21671

Answers (8)

Volk64
Volk64

Reputation: 33

As many people pointed out, you are using the values of your for-each loop as and index, meaning your code tries to access the position of whatever number your user inputs in your array.

So to fix it, you just need to do

smallest = i;

and

largest = i;

Upvotes: 0

Brett Okken
Brett Okken

Reputation: 6306

In java 8, you can obtain an IntStream and get the summary statistics.

final IntSummaryStatistics stats = IntStream.of(numbers).summaryStatistics();

Upvotes: 0

Bubletan
Bubletan

Reputation: 3863

Your problem is related to the way you use the for-loop as already stated in the other answers. A shorter approach in Java 8 though, would be using a stream:

IntStream.of(numbers).max() and IntStream.of(numbers).min()

Upvotes: 2

Ace McCloud
Ace McCloud

Reputation: 900

Change it to :

for (int i=0 ;i< numbers.length; i++) {
            if (numbers[i] < smallest) {
                smallest = numbers[i];
            } // end finding smallest
            else if (numbers[i] > largest) {
                largest = numbers[i];
            } // end finding largest number 
        }

AND <= to <

for (int counter = 0; counter < numbers.length; counter++) {
            System.out.printf("%5d%8d\n", counter, numbers[counter]);
        }

Try catch block will simply handle your error in a graceful way . It won't solve your problem.

Upvotes: 0

AlexR
AlexR

Reputation: 115328

Your problem is in this loop:

for (int i : numbers) {

This loop means iterates over the elements of the array, not its indexes. So, you can say:

for (int a : numbers) {
   if(a > ...) {
   ....
}

Alternatively you can use array index like the following"

for (int i = 0; i < numbers.lenth; i++) {
   if(numbers[i] > ...) {
   .....
}

Upvotes: 0

almeynman
almeynman

Reputation: 7398

CHange 

for (int i : numbers) {

to

for (int i=0;i<numbers.length;i++) {

Upvotes: 0

Danny
Danny

Reputation: 1760

A try-catch would just swallow the exception. Your problem is that the enhanced for loop is iterating over the values of the array, but you're treating it like it's the index, so you check numbers[454] and immediately blow up because you're outside the length of the array.

Either iterate over the indexes, or just work with the values directly:

for (int i : numbers) {
    if (i < smallest) {
        smallest = i;
    } // end finding smallest
    else if (i > largest) {
        largest = i;
    } // end finding largest number 
} // end finding largest and smallest values

Upvotes: 1

mtyurt
mtyurt

Reputation: 3449

for (int counter = 0; counter <= numbers.length; counter++)

You put =<, instead you should put <. if counter equals to length, it tries to reach out of range because indexes start from zero.

Upvotes: 1

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