2.23leapyear.java

JAVA程序设计的源代码

class LeapYear1{
void isLeapyear(int year)    //进行闰年判断的第一种方法
{
if((year%4==0&&year%100!=0)||(year%400==0)){    
System.out.println(year+" is a leap year.");
}else{
System.out.println(year+" is not a leap year");
}
}
}

class LeapYear2{
void isLeapyear(int year)    //进行闰年判断的第二种方法
{
boolean leap;
if(year%4!=0){    
leap=false;
}else if(year%100!=0){    //同一事件第二种条件判断用else if
leap=true;
System.out.println("A");
}else if(year%400 ==0){
leap=false;
}else{    ////同一事件最后一种条件用else
leap=true;
System.out.println("b");
}
if(leap==true){
System.out.println(year+" is a leap year.");
}else{
System.out.println(year+" is not a leap year.");
}
}
}

class LeapYear3{    //进行闰年判断的第一种方法
void isLeapyear(int year)   
{
boolean leap;
if(year%4==0){    //注意分析if和else的配对
if(year%100==0){
if(year%400==0){
leap=true;
}else{
leap=false;
}
}else{
leap=false;
}
}else{
leap=false;
}
if(leap==true){
System.out.println(year+" is a leap year.");
}else{
System.out.println(year+" is not a leap year.");
}
}
}



public class LeapYear{
public static void main(String args[]){
LeapYear1 ly1 = new LeapYear1();
LeapYear2 ly2 = new LeapYear2();
LeapYear3 ly3 = new LeapYear3();
ly1.isLeapyear(1989);    //用不同的方法进行闰年判断
ly2.isLeapyear(2000);
ly3.isLeapyear(2050);
}
}