简单的java程序

1.二分查找，java的输入与输出

package com;


public class Firstapp{
    public static void main(String args[])
    {
        java.util.Scanner sc=new java.util.Scanner(System.in);
        int n,start,end,middle;
        System.out.println("请输入：");
        n=sc.nextInt();
        int a[]={-2,1,4,5,8,12,17,23,45,56,90,100};
        start=0;
        end=a.length-1;
        middle=(start+end)/2;
        int count=0;
        while(n!=a[middle]){
            if(n>a[middle]){
                start=middle;
            }
            else if(n<a[middle]){
                end=middle;
            }
                middle=(start+end)/2;
                count++;
                if(count>a.length/2)    
                    break;
            }
        if(count>a.length/2)
            System.out.println(":"+n+"不在数组内");
        else
            System.out.println(":"+n+"是数组中第"+middle+"个元素");
        
        }
    }

 2.java的类与对象，new对对象进行初始化

package com;
class XiyouRenwu { float height,weight;
String head, ear,hand,foot,mouth;
void speak(String s)
{ 
   head="歪着头";
   System.out.println(s);
}
}

public class Exmple {    
    public static void main(String args[])
    {XiyouRenwu zhubajie,sunwukong;
    zhubajie=new XiyouRenwu();
    sunwukong=new XiyouRenwu();
    zhubajie.height=1.80f;                                //对象给自己的变量赋值。
    zhubajie.weight=160f;      
    zhubajie.hand="两只黑手";
    zhubajie.foot="两只大脚"; 
    zhubajie.head="大头"; 
    zhubajie.ear="一双大耳朵"; 
    zhubajie.mouth="一只大嘴"; 
    sunwukong.height=1.62f;                                //对象给自己的变量赋值。
    sunwukong.weight=1000f;    
    sunwukong.hand="白嫩小手";
    sunwukong.foot="两只绣脚"; 
    sunwukong.head="绣发飘飘"; 
    sunwukong.ear="一对小耳";  
    sunwukong.mouth="樱桃小嘴";
    System.out.println("zhubajie的身高："+zhubajie.height);
    System.out.println("zhubajie的头："+zhubajie.head);
    System.out.println("sunwukong的重量："+sunwukong.weight);
    System.out.println("sunwukong的头："+sunwukong.head);
    zhubajie.speak("俺老猪我想娶媳妇");                       //对象调用方法。
    System.out.println("zhubajie现在的头："+zhubajie.head);
    sunwukong.speak("老孙我重1000斤，我想骗八戒背我");         //对象调用方法。
    System.out.println("sunwukong现在的头："+sunwukong.head);

    }

}