书上的例题

public class Tom {
int leg;
String head ;
void cry (String s){
System.out.println(s);
}
}
class Example{
public static void main (String args[]){
Tom cat ;
cat = new Tom();
cat.leg=4;
cat.head="maotou";
System.out.println("tui :"+cat.leg+"tiao");
System.out.println("tou:"+cat.head);
cat.cry("woyaohe");

}

}

第13页 例2-1
public class Example2_1 {


/**
* @param args
*/
public static void main(String[] args) {
char c='a';
System.out.println("zimu" + c +"zaibiaozhongdeweizhi "+(int)c);
System.out.println("zimubiao");
for(int i =(int)c;i<c+25;i++){
System.out.print(""+(char)i);
}


}


}

第15页 例2-2
public class Example2_2 {


/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stu
byte a =120;
short b=130;
int c=2200;
long d=80000;
float f;
double g=0.12345676812345678;
a=(byte)b;
c=(int)d;
f=(float)g;
System.out.println("a="+a);
System.out.println("c="+c);
System.out.println("f="+f);
System.out.println("g="+g);


}


}

第16页 例2-4

import java.util.*;


import javax.print.DocFlavor.READER;




public class Example2_4 {


/**
* @param args
*/
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
double sum =0;
int m =0;
while(reader.hasNextDouble()){
double x=reader.nextDouble();
m=m+1;
sum=sum+x;

}
System.out.println(m);
System.out.println(m+"geshudeheshi"+sum);
System.out.println(m+"geshudepingjunshu"+sum/m);
}


}

第24页 例3-1

import java.util.Scanner;




public class Example3_1 {


/**
* @param args
*/
public static void main(String[] args) {
Scanner reader =new Scanner(System.in);
System.out.println("输入待移位的int型整数： ");
int x =reader.nextInt();
System.out.println("输入位移量： ");
int n =reader.nextInt();
System.out.println("左移位的结果是： "+(x<<n));
System.out.println("右移位的结果是： "+(x>>n));
}


}

第25页 例3-2
public class Example3_2 {


/**
* @param args
*/
public static void main(String[] args) {
char a[]={'金','木','水','火','土'};
char secret ='z';
for (int i = 0;i<a.length;i++){
a[i]=(char)(a[i]^secret);
}
System.out.println("密文：");
for(int i=0;i<a.length;i++){
System.out.print(a[i]);

}
System.out.println("");
for(int i=0;i<a.length;i++){
a[i]=(char)(a[i]^secret);
}
System.out.println("原文：");
for(int i=0;i<a.length;i++){
System.out.print(a[i]);
}

}


}

第28页 例3-3

import java.util.Scanner;




public class Example3_3 {


/**
* @param args
*/
public static void main(String[] args) {
Scanner reader =new Scanner(System.in);
double a =0,b=0,c=0;
System.out.println("shurubian a ");
a=reader.nextDouble();
System.out.println("shsurubian b");
b=reader.nextDouble();
System.out.println("shurubian c");
c=reader.nextDouble();
if(a+b>c&&a+c>b&&b+c>a){
if(a*a==b*b+c*c||b*b==a*a+c*c||c*c==a*a+b*b){
System.out.println(a+" "+b+" "+c+" gouchengzhijiaosanjiaoxing");
}
else if (a*a<b*b+c*c&&b*b<a*a+c*c&&c*c<a*a+b*b) {
System.out.println(a+" "+b+" "+c+" gouchengruijiaosanjiaoxing");

}
else{
System.out.println(a+" "+b+" "+c+" gouchengdunjiaosanjiaoxing");
}
}
else{
System.out.println(a+" "+b+" "+c+" bunenggouchengsanjiaoxing");
}
}


}

第29页 例3-4

import java.util.Scanner;




public class Example3_4 {


/**
* @param args
*/
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
System.out.println("shuruyigeyuefen: ");
int n= reader.nextInt();
switch (n) {
case 1:
case 2:
case 3:System.out.println(n+"yueshuyudiyijidu");
  break;
case 4:
case 5:
case 6:System.out.println(n+"yueshuyudierjidu");
break; 
case 7:
case 8:
case 9:System.out.println(n+"yueshuyudisanjidu");
break;
case 10:
case 11:
case 12:System.out.println(n+"yueshuyudisijiadu");
break;
default:System.out.println(n+"budaibiaoyuefen");
}
}


}

第31页 例3-5

public class Example3_5 {


/**
* @param args
*/
public static void main(String[] args) {
double sum = 0,item=1;
int i= 1;
while (i<=1000) {
sum=sum+item;
i++;
item=item*(1.0/i);
}
sum=sum+1;
System.out.println("e="+sum);
sum=0;
i=1;
item=1;
do {
sum=sum+item;
i++;
item=item*(1.0/i);
} while (i<1000);
sum=sum+1;
System.out.println("e="+sum);
}


}

第32页 例3-6
public class Example3_6 {


/**
* @param args
*/
public static void main(String[] args) {
int sum,i,j;
for(i=1;i<=1000;i++){
for (j = 1,sum=0;j<=i/2; j++) {
if(i%j==0){
sum=sum+j;
}
}
if(sum==i){
System.out.println(i+"shiyigewanshu");
}
}


}


}

第32页 例3-7

public class Example3_7 {


/**
* @param args
*/
public static void main(String[] args) {
int sum=0,i=0,max=8888,number=7;
while (true) {
i++;
sum=sum+i;
if(sum>=max)
break;

}
System.out.println("1+2+……+n<"+max+"dezuidazhengshu n shi :"+(i-1));
for(i=1,max=200,sum=0;i<=max;i++){
if(i%number!=0){
continue;
}
sum=sum+i;

}
System.out.println(max+"neinengbei"+number+"zhengchudeshuzizhihe :"+sum);

}




}

第33页 例3-8

import java.util.Scanner;








public class Example3_8 {


/**
* @param args
*/
public static void main(String[] args) {
int n,start,end,middle;
int a[]={-2,1,4,5,8,12,17,23,45,56,90,100};
start =0;
end=a.length;
middle=(start+end)/2;
int count =0;
Scanner reader=new Scanner(System.in);
System.out.println("qingshuruyigezhengshu :");
n=reader.nextInt();
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+"buzaisuzuzhong");
else 
System.out.println(n+"shishuzuzhongdediyige"+middle+"geyuansu");
}


}