示例: 实现二分搜索算法的 Java 程序
import java.util.Scanner; // Binary Search in Java class Main { int binarySearch(int array[], int element, int low, int high) { // Repeat until the pointers low and high meet each other while (low <= high) { // get index of mid element int mid = low + (high-low) / 2; // if element to be searched is the mid element if (array[mid] == element) return mid; // if element is less than mid element // search only the left side of mid if (array[mid] < element) low = mid + 1; // if element is greater than mid element // search only the right side of mid else high = mid-1; } return -1; } public static void main(String args[]) { // create an object of Main class Main obj = new Main(); // create a sorted array int[] array = { 3, 4, 5, 6, 7, 8, 9 }; int n = array.length; // get input from user for element to be searched Scanner input = new Scanner(System.in); System.out.println("Enter element to be searched:"); // element to be searched int element = input.nextInt(); input.close(); // call the binary search method // pass arguments: array, element, index of first and last element int result = obj.binarySearch(array, element, 0, n-1); if (result ==-1) System.out.println("Not found"); else System.out.println("Element found at index " + result); } }
输出 1
Enter element to be searched: 6 Element found at index 3
在这里，我们使用了 Java Scanner Class 来获取用户的输入。根据用户的输入，我们使用二进制搜索来检查元素是否存在于数组中。
我们也可以使用递归调用来执行相同的任务。
int binarySearch(int array[], int element, int low, int high) { if (high >= low) { int mid = low + (high-low) / 2; // check if mid element is searched element if (array[mid] == element) return mid; // Search the left half of mid if (array[mid] > element) return binarySearch(array, element, low, mid-1); // Search the right half of mid return binarySearch(array, element, mid + 1, high); } return -1; }
此处，方法
binarySearch() 会调用自身，直到找到元素或
if 条件失败。
如果您想了解有关二分搜索算法的更多信息，请访问二分搜索算法。
