In the first 11 days of learning of the striker;
JAVA_DAY9;
course today to learn knowledge of recursive functions, arrays, and so on;
!! Come on, China World refuel
myself Come on!
class TestYearAndMonth
{
//判定给定的year是否是闰年,如果是返回true,否则返回false
public static boolean leapYear(int year1){
if((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)){
System.out.println("是闰年啊");
return true;
}else{
System.out.println("不是润年,是平年。。");
return false;
}
}
//返回给定year这个年里,month这个月的天数
public static int getDaysOfMonth(int year2,int month){//year=2020,month=2
int days = 0;//用于表示month这个月的天数
switch(month){
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
days = 31;
break;
case 4:
case 6:
case 9:
case 11:
days = 30;
break;
case 2:
if(leapYear(year2)){//boolean类型
days = 29;
}else{
days = 28;
}
break;
}
return days;
}
public static void main(String[] args)
{
//练习1:设计一个方法,用于判断给定的年份是否是闰年
//练习2:设计一个方法,用于返回给定年份中这个月份的天数
//1,3,5,7,8,10,12-->31天
//4,6,9,11-->30天
//2,--->29/28
boolean res1 = leapYear(2020);
System.out.println(res1);
int res2 = getDaysOfMonth(2030,2);
System.out.println(res2);
System.out.println("Hello World!");
/*
两个方法给的形参算是局部变量,可以重名不影响
*/
}
}
public class Test1Recursion
{
//递归方法
public static int getSum(int n){
System.out.println("******");
if(n == 1){
return 1;
}else{
return getSum(n - 1) + n;
}
}
public static void main(String[] args){
/*
求1-5的和:
+1+2+3+4+5
+1+2+3+4 +5
求1-n的和:getSum(n),该方法用于表示求1-n的和。
getSum(5)
:getSum(4) + 5
:getSum(3) + 4
:getSum(2) + 3
getSum(1) + 2
1
*/
int res = getSum(5);
System.out.println(res);
Scanner sc = new Scanner(System.in);
int num = sc.nextInt();
}
}