Question

How to reverse an array upto a given index in JavaScript

Answer 1

function reverseUpToIndex(arr, index) {
    if (index > arr.length) {
        console.log("Index out of range");
        return;
    }
       
    for (let i = 0; i < index / 2; i++) {
        let temp = arr[i];
        arr[i] = arr[index - i - 1];
        arr[index - i - 1] = temp;            
    }
}
 
 
const arr = [ 1, 4, 8, 0, 7, 3, 9, 5, 6 ];
          
const index = 5;
          
reverseUpToIndex(arr, index);
   
console.log(arr);
 
   
   
   
   
/*
run:
   
[7, 0, 8, 4, 1, 3, 9, 5, 6]
   
*/

 

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