publicclassApp1{publicstaticvoidmain(String[] args){// TODO Auto-generated method stub
System.out.println("hello,world");}}
2.welcome
import java.util.*;publicclasswelcom{publicstaticvoidmain(String[] args){// TODO Auto-generated method stub
Scanner s =newScanner(System.in);
System.out.println("Hello!What's your name :");
String name = s.nextLine();
System.out.println(name+",Welcome to learn OOP using java!");}}
3.求五边形的面积和周长
import java.util.Scanner;publicclassArea{publicstaticvoidmain(String[] args){// TODO Auto-generated method stub
Scanner number =newScanner(System.in);double r = number.nextDouble();
System.out.printf("%.4f",(r*r*(Math.sqrt(25+10*Math.sqrt(5)))/4));
System.out.printf("\n");
System.out.printf("%.0f",5*r);}}
import java.util.Scanner;publicclassExam2_7{publicstaticvoidmain(String[] args){// TODO Auto-generated method stubboolean x,y,z,a,b;
a ='c'>'C';
b ='r'!='r';
x =!a;
y = a && b;
z = a || b;
System.out.println("x="+x);
System.out.println("y="+y);
System.out.println("z="+z);
System.out.println("a="+a);
System.out.println("b="+b);}}