How to reverse an array without a loop or creating new array [closed]

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class ReverseArrayElements1
{
  public static void main ( String[] args )
  {
    int[] values = {10, 20, 30, 40}; 
    int temp;

     System.out.println( "Original Array: " + values[0] + "\n" + values[1] +
                         "\n" + values[2] + "\n" + values[3]   );

    // reverse the order of the numbers in the array



    System.out.println( "Reversed Array: " + values[0] + "\n" + values[1] + "\n"
                         + values[2] + "\n" + values[3] );
   }
}

Task I need to complete the program so that the numbers in the array appear in reversed order. This does not mean that I can just need to display the elements in reverse order; I will actually move the last element in the array into the the first element of the array, and so on. I can't use a loop or create a new array.

The output should be

Original Array: 10 20 30 40 
Reversed Array: 40 30 20 10

Without using iteration or recursion - this seems to be an impossible task. And also, it seems to be crowd sourcing a homework problem with little effort shown, so I am voting to close. See: stackoverflow.com/questions/11322514/… — sleepToken
– sleepToken, Commented Dec 3, 2019 at 18:30
This is what the teacher told me. I am lost as you. I don't really even know where to begin. — ikkkkkkkkkkkkkkkhjhkj
– ikkkkkkkkkkkkkkkhjhkj, Commented Dec 3, 2019 at 18:31
Can you swap them manually like temp = arr[0]; arr[0]= arr[3]; arr[3]=tmp; to swap border values, and then temp = arr[1]; arr[1]=arr[2]; arr[2]=tmp; to swap middle values. — Pshemo
– Pshemo, Commented Dec 3, 2019 at 18:35

sleepToken · Accepted Answer · 2019-12-03 18:15:09Z

2

If you're using Java 8:

import java.util.stream.IntStream;

// stuff

int[] reversed = IntStream.range(0,values.length).map(i -> values[values.length-i-1]).toArray();

answered Dec 3, 2019 at 18:15

sleepToken

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3 Comments

ikkkkkkkkkkkkkkkhjhkj Over a year ago

You can't use other libraries. That defeats the purpose

sleepToken Over a year ago

I was attempting to answer the question I was given. Since you didn't specify restriction of external libraries in your question, I believe I did my best. In that case, it sounds like this is an assignment to practice recursion - and seeing as this question doesn't show your prior attempts I am voting for this question to be closed.

ikkkkkkkkkkkkkkkhjhkj Over a year ago

Our teacher said to redefine the arraylist.

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