第三周作业-循环与判断语句

类名：MathDemo

public class MathDemo {
public static void main(String[] args){
System.out.println("abs(-5)="+Math.abs(-5));
System.out.println("max(6.75,3.14)="+Math.max(6.75,3.14));
System.out.println("min(100,200)="+Math.min(100,200 ));
System.out.println("round(3.5)="+Math.round(3.5));
System.out.println("round(-6.5)="+Math.round(-6.5));
System.out.println("sqrt(2)="+Math.sqrt(2));
System.out.println("pow(2,5)="+Math.pow(2,5));
System.out.println("E="+Math.E);
System.out.println("exp(2)="+Math.exp(2));
System.out.println("log(2)="+Math.log(2));
System.out.println("ceil(6.75)="+(int)Math.ceil(6.75));
System.out.println("floor(6.75)="+(int)Math.floor(6.75));
System.out.println("Pi="+Math.PI);
System.out.println("sin(Pi/4)="+Math.sin(Math.PI/4));
System.out.println("cos(1)="+Math.cos(1));

}

}

public class LoopExample
{
public static void main(String[] args)
{
int lay=4;
for(int i=1;i<=lay;i++)
{
for(int k=1;k<=lay-i;k++)
{
System.out.print(" ");
}

for(int j=1;j<=2*i-1;j++)
{
System.out.print("*");
}
System.out.println( );
}
}
}

类名：CalculatePi

public class CalculateP {
public static void main(String args[]){
double sum = 0.0;

for(int i = 1; i <= 70000000; i +=4){
sum += (1.0/i - 1.0/(i+2));
}

double pi = 4*sum;

System.out.println("pi="+pi);

}

}

类名：LeapYear

import java.util.Scanner;
public class LeapYear {
public static void main(String[] args){

//Creat a Scanner
Scanner input = new Scanner(System.in);
System.out.print("Enter a year:");
int year = input.nextInt();

//Check if the year is a leap year
boolean isLeapYear=(year % 4 ==0 && year % 100 !=0) || (year % 400 == 0);

//Display the result
System.out.println(year + "is a leap year?" + isLeapYear);
}

}