I'm trying to create a program that allows the user to input numbers into a array called "numArray", however an exception is thrown once the user inputs numbers into array. How can this be fixed?
import java.util.Scanner;
class ArrayNumList
{
public static void main(String[]args)
{
Scanner in = new Scanner(System.in);
System.out.println("How many nums would you like to enter? ");
int n = in.nextInt();
System.out.println("Enter " + n + " nums");
int[] numArray = new int[n];
for(int i = 0; i <= n; i++)
{
int index = in.nextInt();
System.out.print(numArray[index]);
}
}
}
There is no index
index if the user inserts a big enough number / negative number. Fix it by using the actual loop variable i
like this:
for(int i = 0; i <= n; i++) {
numArray[i] = in.nextInt();
System.out.print(numArray[i]);
}
The problem is that you aren't storing your data anywhere in the array.
for(int i = 0; i <= n; i++)
{
int index = in.nextInt();
System.out.print(numArray[index]);
}
Every time you run through the array, you store your input into the variable index
. From there, you try to display the value in your array at that index. This can lead to a few problems.
1) You haven't put your numbers into this array yet, so each value in the array is going to be 0. To fix this:
numArray[i] = in.nextInt();
2) If someone inputs a number that's bigger than the size of your array, you'll get an IndexOutOfBoundsException
. I don't think you were trying to do it this way, but this is what your code is currently attempting to do.
There are 3 issues:-
1) Use i < n as you start from 0
2) Trying to add input value as index in the array.
3) Printing out the values while entering which create confusion for you better to do that in separate loop but I leave it to u or Better to use println instead of print
Try this:-
public static void main(String[]args) {
Scanner in = new Scanner(System.in);
System.out.println("How many nums would you like to enter? ");
int n = in.nextInt();
System.out.println("Enter " + n + " nums");
int[] numArray = new int[n];
for(int i = 0; i < n; i++)
{
numArray[i] = in.nextInt();
System.out.println(numArray[i]);
}
}
Firstly it should be i<n
and not i<=n
because n
means the array length and i
means the array index. The index starts from 0. For eg an array holds the values 1234, so the length is 4 but the index are 0,1,2,3. So the index is always one less than the array length. Also you have to store the input with the array index.
for(int i = 0; i < n; i++)
{
numArray[i] = in.nextInt();
}
And then later print it
for(int i = 0; i < n; i++)
{
System.out.println(numArray[i]);
}
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.