Create a function, say binarySearch() that takes in 4 arguments −
- a sorted Number / String literal array
- starting index of array (0)
- ending index of array (length - 1)
- number to be searched
If the number exists in the array, then the index of the number should be returned, otherwise -1 should be returned. Here is the full code −
Example
const arr = [2,4,6,6,8,8,9,10,13,15,17,21,24,26,28,36,58,78,90]; //binary search function //returns the element index if found otherwise -1 const binarySearch = (arr, start, end, num) => { const mid = start + Math.floor((end - start)/2); if(start <= end){ if(arr[mid] === num){ return mid; } if(num < arr[mid]){ return binarySearch(arr, start, mid-1, num); } if(num > arr[mid]){ return binarySearch(arr, mid+1, end, num); } } return -1; }; console.log(binarySearch(arr, 0, arr.length-1, 13)); console.log(binarySearch(arr, 0, arr.length-1, 11));
Output
The output of this code in the console will be −
8 -1