binarysearch.java

数据结构与算法分析设计的实验作业

public class BinarySearch
{
	
	public static int binarysearch(int[] a,int x,int n)
	{
		int left=0;int right=n-1;
		while(left<=right)
		{
			int middle=(left+right)/2;
			if(x==a[middle])return middle;
			if(x>a[middle]) left=middle+1;
			else right=middle-1;
		}
		return -1;
	}
	public static void main(String args[])
	{
		int a[]={12,14,16,20,22,25,36};
		int key=Integer.parseInt(args[0]);
		int k=binarysearch(a,key,a.length);
		if(k!=-1)
		System.out.println("found value in element:"+k);
		else
		System.out.println("key not found");
	}
}