练习

import java.util.Random;
public class mytest {

    public static void main(String[] args) {
        Random rand = new Random();
        int[] aa ;
        int len = 100;
        aa = new int[len];
        for(int i = 0 ;i < len ;i++)
        {
            aa[i] = rand.nextInt(len);
        }
        //sort
        for(int i = 0 ; i < len ; i ++){
            for(int j = i ; j < len ; j ++){
                if(aa[i]>aa[j]){
                    int tmp = aa[i];
                    aa[i] = aa[j];
                    aa[j] = tmp;
                }
            }            
        }
        //print
        for(int i = 0 ; i < len ; i ++){
            System.out.println(aa[i]);            
        }
        System.out.println("--------------------------------------------");
        //find
        int searchVal = 77;
        int resultPos = searchInt(aa,searchVal,0,len);
        System.out.println(resultPos);

        System.exit(0);
    }
    
    public static int searchInt(int[] intArr,int searchV,int beginIndex,int endIndex){
        int modPs = beginIndex + ( endIndex - beginIndex ) / 2;
        if(intArr[modPs]==searchV){
            return modPs;
        }else if(endIndex < beginIndex || endIndex - beginIndex == 1){
            return -1;
        }else if(intArr[modPs]<searchV){
            beginIndex = modPs;
            return searchInt(intArr,searchV,beginIndex,endIndex);
        }else{
            endIndex = modPs;
            return searchInt(intArr,searchV,beginIndex,endIndex);
        }
    }
}