Java: Arrays Question

[zk0]

Hi!

I have a question regarding arrays in Java.

I want a user to (1) decide how many numbers he want to type in and store in the array. (2) Let the user type in the numbers. (3) Show the numbers from the array backwards.

THis is how my code looks like now. What am I doing wrong? Can anyone point me in the right direction? Thanks in advanced! :)

import java.util.Scanner;

public class steg4egenlabb2 {

public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);
int tal = 0;

System.out.print("Enter the amount of numbers you want to store in the array : ");
tal = keyboard.nextInt();

System.out.println("Enter " + tal + " numbers:");

int[] antal = new int[tal];

antal[0] = keyboard.nextInt();

System.out.println("The numbers written backwards:");
System.out.println(antal[0]);

}
}


This is how it currently shows with that code (text marked with bold is the text that the user types in):

Enter the amount of numbers you want to store in the array : 5
Enter 5 numbers:
1 2 3 4 5
The numbers written backwards:
1

[nikkiH]

Is there some reason you're not just using a more dynamic storage class, such as ArrayList or Vector?

That said, you're only outputting the first element. [0].

[ess]

Hello there,

I have taken the liberty to rewrite your class in order to help you out.

import java.util.Scanner;

public class steg4egenlabb2 {

public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);
int tal = 0;

System.out.print("Enter the amount of numbers you want to store in the array : ");
tal = keyboard.nextInt();

int[] antal = new int[tal];

// loop array elements and get values from the user
for( int i = 0; i < tal; i++ ) {
System.out.print( "Enter Value for Element " + (i+1) + ": " );
antal[i] = keyboard.nextInt();
}

System.out.println("The numbers written backwards:");
// loop through the array backwards and output the values.
for( int i = antal.length - 1; i >= 0; i-- ) {
System.out.println( "Element at position " + ( 1 + i ) + " is: " +antal[i]);
}

}
}

the output of running this program is

Enter the amount of numbers you want to store in the array : 5
Enter Value for Element 1: 1
Enter Value for Element 2: 2
Enter Value for Element 3: 3
Enter Value for Element 4: 4
Enter Value for Element 5: 5
The numbers written backwards:
Element at position 5 is: 5
Element at position 4 is: 4
Element at position 3 is: 3
Element at position 2 is: 2
Element at position 1 is: 1

Good luck.
Ess

[zk0]

Is there some reason you're not just using a more dynamic storage class, such as ArrayList or Vector?

That said, you're only outputting the first element. [0].

Sorry that is too advanced for me right now :/

[zk0]

Hello there,

I have taken the liberty to rewrite your class in order to help you out.

import java.util.Scanner;

public class steg4egenlabb2 {

public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);
int tal = 0;

System.out.print("Enter the amount of numbers you want to store in the array : ");
tal = keyboard.nextInt();

int[] antal = new int[tal];

// loop array elements and get values from the user
for( int i = 0; i < tal; i++ ) {
System.out.print( "Enter Value for Element " + (i+1) + ": " );
antal[i] = keyboard.nextInt();
}

System.out.println("The numbers written backwards:");
// loop through the array backwards and output the values.
for( int i = antal.length - 1; i >= 0; i-- ) {
System.out.println( "Element at position " + ( 1 + i ) + " is: " +antal[i]);
}

}
}

the output of running this program is

Enter the amount of numbers you want to store in the array : 5
Enter Value for Element 1: 1
Enter Value for Element 2: 2
Enter Value for Element 3: 3
Enter Value for Element 4: 4
Enter Value for Element 5: 5
The numbers written backwards:
Element at position 5 is: 5
Element at position 4 is: 4
Element at position 3 is: 3
Element at position 2 is: 2
Element at position 1 is: 1

Good luck.
Ess

Thank you! I see now. I needed a for loop. I've made some changes to the code and now it looks more the way I want it to:

import java.util.Scanner;

public class steg4egenlabb2 {

public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);
int tal = 0;

System.out.print("Ange antalet heltal du vill lagra i arrayen: ");
tal = keyboard.nextInt();

System.out.println("Ange " + tal + " heltal:");

int[] antal = new int[tal];

for( int i = 0; i < tal; i++ ) {
antal[i] = keyboard.nextInt();
}

System.out.println("Talen utksrivna baklänges:");

for( int i = antal.length - 1; i >= 0; i-- ) {
System.out.print(antal[i] + " ");
}
}
}


:thumbsup: