编辑代码

function binarySearch(arr, target) {
  let low = 0;
  let high = arr.length - 1;

  while (low <= high) {
    let mid = low +(high -  low) >> 1;
    if (arr[mid] === target) {
      return mid; // 找到目标元素，返回索引
    } else if (arr[mid] < target) {
      low = mid + 1; 
    } else {
      high = mid - 1; 
    }
  }

  return -1;
}


const arr = [1, 3, 5, 7, 9, 11, 13];
const target = 7;

const result = binarySearch(arr, target);
if (result !== -1) {
  console.log(`目标元素 ${target} 的索引为 ${result}`);
} else {
  console.log(`目标元素 ${target} 不存在于数组中`);
}