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);

     }

 }