Searching

Binary Search:

	 public class BinarySearch {
		
			public static void main(String[] args) {
				int arr[]={2,4,8,12,15};
				int key=4;
				System.out.println("Index value is ="+binarySearch(arr,key));
			}
		
			private static int binarySearch(int[] arr, int key) {
				int start=0;
				int end=arr.length-1;
				int mid=0;
				int index=-1;
				while (start < end) {
					mid=(start+end)/2;
					if (arr[mid]==key) {
						index=mid;
						break;
					}
					else if (key < arr[mid]) {
						end=mid;
					}else {
						start=mid;
					}
				}
				return index;
			}
			
		}