Example2_5

import java.util.Scanner;
public class Example2_5 {
    public static void main(String args[]){
        int start=0,end,middle;
        int a[]={12,45,67,89,123,-45,67};
        int N=a.length;
        for(int i=0;i<N;i++){
            for(int j=i+1;j<N;j++){
                if(a[j]<a[i]){
                    int t=a[i];
                    a[i]=a[j];
                    a[j]=t;
                }
            }
        }
        Scanner scanner=new Scanner(System.in);
        System.out.println("输入整数，程序判断该整数是否在数组中：");
        int number=scanner.nextInt();
        int count=0;
        end=N;
        middle=(start+end)/2;
        while (number!=a[middle]){
            if(number>a[middle])    start=middle;
            else if(number<a[middle])   end=middle;
            middle=(start+end)/2;
            count++;
            if(count>N/2)   break;
        }
        if(count>N/2)   System.out.printf("%d不在数组中.\n",number);
        else    System.out.printf("%d在数组中.\n",number);
    }
}

非法标识符 

float 

 char

 基本类型

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