（Java数据结构和算法）数组------二分查找

//有序数组类
public class Main{
	private int[] a;//数组a,封死在里面，不能让外界访问
	private int size;//数组大小
	private int elementNumber;//数组当前元素个数

	public Main(int n){
		a = new int[n];
		size = n;
		elementNumber = 0;
	}
	
	public int getElementNumer(){
		return elementNumber;
	}

	//在从小到大排序的基础上，二分查找
	public int find(int value){
		int low = 0;
		int high = elementNumber - 1;
		int mid;
		
		while(true){
			mid = (low + high) / 2;
			if(a[mid] == value){
				return mid;
			}else if(low > high){
				return elementNumber;//没找到，返回元素个数
			}else{
				if(a[mid] < value){
					low = mid + 1;
				}else{
					high = mid - 1;
				}
			}
		}
	}

	//插入，保证从小到大排序
	public boolean insert(int value){
		//如果数组容量用尽，不可再插入
		if(elementNumber >= size){
			return false;
		}
		int i;
		for(i = 0; i < elementNumber; i++){
			if(a[i] > value){
				break;
			}
		}
		for(int j = elementNumber; j > i; j--){
			a[j] = a[j-1];//不要用a[j+1] = a[j];防止数组越界
		}
		a[i] = value;
		elementNumber++;
		return true;
	}

	//删除
	public boolean delete(int value){
		int i = find(value);
		if(i == elementNumber){
			return false;
		}else{
			for(int j = i + 1; j < elementNumber; j++){
				a[j-1] = a[j];
			}
			elementNumber--;
			return true;
		}
	}
	
	//打印数组
	public void print(){
		for(int i = 0; i < elementNumber; i++){
			System.out.print(a[i] + " ");	
		}
		System.out.println();
	}

	//测试
	public static void main(String[] args){
		int maxSize = 100;
		Main orderedArray = new Main(maxSize);
		orderedArray.insert(77);
		orderedArray.insert(99);
		orderedArray.insert(44);
		orderedArray.insert(55);
		orderedArray.insert(22);
		orderedArray.insert(88);
		orderedArray.insert(11);
		orderedArray.insert(00);
		orderedArray.insert(66);
		orderedArray.insert(33);

		int searchKey = 55;
		if(orderedArray.find(searchKey) != orderedArray.getElementNumer()){
			System.out.println(searchKey+" found, index = "+orderedArray.find(searchKey));
		}else{
			System.out.println(searchKey+" not found");
		}
		
		orderedArray.print();
		
		orderedArray.delete(00);
		orderedArray.delete(55);
		orderedArray.delete(99);
		
		orderedArray.print();
		
	}
}