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javaarraysinput
Dan
Dan

Reputation: 195

How do I fill an array with consecutive numbers

I would like to fill an array using consecutive integers. I have created an array that contains as much indexes as the user enters:

Scanner in = new Scanner(System.in);
int numOfValues = in.nextInt();

int [] array = new int[numOfValues];

How do i fill this array with consecutive numbers starting from 1? All help is appreciated!!!

Upvotes: 16

Views: 21330

Answers (7)

gooooof
gooooof

Reputation: 41

int[] arr = new int[5];
Arrays.setAll(arr, i -> 2 + i);
// arr ==> int[5] { 2, 3, 4, 5, 6 }

Upvotes: 1

Dan
Dan

Reputation: 195

Scanner in = new Scanner(System.in);
int numOfValues = in.nextInt();

int[] array = new int[numOfValues];

int add = 0;

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

    array[i] = 1 + add;

    add++;

    System.out.println(array[i]);

}

Upvotes: -2

arena
arena

Reputation: 378

One more thing. If I want to do the same with reverse:

int[] array = new int[5];
        for(int i = 5; i>0;i--) {
            array[i-1]= i;
        }
        System.out.println(Arrays.toString(array));
}

I got the normal order again..

Upvotes: 0

Sotirios Delimanolis
Sotirios Delimanolis

Reputation: 280132

Since Java 8

//                               v end, exclusive
int[] array = IntStream.range(1, numOfValues + 1).toArray();
//                            ^ start, inclusive

The range is in increments of 1. The javadoc is here.

Or use rangeClosed

//                                     v end, inclusive
int[] array = IntStream.rangeClosed(1, numOfValues).toArray();
//                                  ^ start, inclusive

Upvotes: 45

dave823
dave823

Reputation: 1211

for(int i=0; i<array.length; i++)
{
    array[i] = i+1;
}

Upvotes: 2

Neverwork2123
Neverwork2123

Reputation: 227

You now have an empty array

So you need to iterate over each position (0 to size-1) placing the next number into the array.

for(int x=0; x<NumOfValues; x++){ // this will iterate over each position
     array[x] = x+1; // this will put each integer value into the array starting with 1
}

Upvotes: 0

Stack Exchange Broke The Law
Stack Exchange Broke The Law

Reputation: 58909

The simple way is:

int[] array = new int[NumOfValues];
for(int k = 0; k < array.length; k++)
    array[k] = k + 1;

Upvotes: 4

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