Java review four

Process Control

Compound statement: {}

Conditional statements 

//one
if(){
}
else{
}
//tow
if(){}
//three
if(){
}
else if(){
}
// at Four 
Switch (expression) {
Constant 1 case: {
BREAK}; 
Case constant 2: { 
} BREAK; 
Case constants. 3: { 
} BREAK; 
default: 
{} 
[BREAK;] 
......

}

loop statement:

while(){
}

do{

}while();

for()

{
}

Out of the loop: continue, break

By calculating a while loop 1 + 1/ 2! + 1/ 3! ... 1/ 20!

package first;

public class a {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
     float sum = 0;
     int i=1;
     long j;
     int k;
     while(i<=20) {         
         j=1;
         for(k=1;k<=i;k++) {
             j*=k;
         }       
         sum+=(1.0/j);
         i++;
     }
     System.out.println(sum);
    }

}

 

Application if statement to determine whether a given year is a leap year

package first;

import java.util.Scanner;

public class a {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
     float sum = 0;
     int year;
     Scanner cin=new Scanner(System.in);
     year=cin.nextInt();
     if((year%100!=0&&year%4==0)||year%400==0)
           System.out.println ( "leap year" );
      the else 
         System.out.println ( "average year" );
    }

}