(JAVA) Populating an array of some size from user input and printing out the elements along with the-CodePudding

I have to prompt the user for an integer value and create an integer array of that size, but I'm not sure how to populate it using a for loop with the values 1… size, and print out the elements of the array preceded by their indices.

Here is a sample execution of the program. The user input is in bold.
How large an array? 5
0: 1
1: 2
2: 3
3: 4
4: 5

Here's what I have so far:

    Scanner sc = new Scanner(System.in);
    
    System.out.print("How large an array? ");
    int i = sc.nextInt();
    int arr [] = new int[i];
    
    
    for (int j = 0; j < i; j  ) {
        System.out.print(arr[i]   ": "); 
    }

CodePudding user response：

Do you mean something like that? I'm not sure if understood your question right.

    Scanner sc = new Scanner(System.in);
    
    System.out.print("How large an array? ");
    int i = sc.nextInt();
    sc.close();
    int[] arr = new int[i];
    
    for (int j = 0; j < i; j  ) {
        arr[j] = j   1;
        System.out.println(j   ": "   arr[j]); 
    }

CodePudding user response：

You have to set the values that should be saved in the array first, before you can access them. That won't happen automatically.

After fixing your code, I came up with this:

Scanner sc = new Scanner( System.in );

System.out.print( "How large should the array be? " );
int size = sc.nextInt();
int[] array = new int[ size ];

//fill array with values
for ( int i = 0; i < size; i   )
    array[ i ] = i   1;

//print values
for ( int i = 0; i < size; i   )
    System.out.println( i   ": "   array[ i ] );

It produces the following answer for input 5:

0: 1
1: 2
2: 3
3: 4
4: 5

I hope this helps you further.

CodePudding user response：

If you don't really need an array, you could this simpler by using Java 8 IntStream range feature:

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        System.out.print("How large an array? ");
        int numbersCount = sc.nextInt();

        List<Integer> numbers = IntStream.range(1, numbersCount   1)
                .boxed()
                .collect(Collectors.toList());

        for (int i = 0; i < numbersCount; i  ) {
            System.out.println(i   ": "   numbers.get(i));
        }
    }
}