java day1

编译命令 javac HelloWorld.java
运行命令 java HelloWorld

Hello World

public class HelloWorld{
        public static void main(String args[]){
                    System.out.println("Hello World");
        };
};

99乘法表

   public class HelloWorld{
        public static void main(String args[]){
           int i,j;
           for(i=0;i<=9;i++){
           System.out.println();
           for(j=1;j<=i;j++){
                 System.out.print(i+"X"+j+"="+i*j+"  ");
           };
        };
        System.out.println();
        };
  };

*****

****

***

**

*

   public class HelloWorld{
        public static void main(String args[]){
           int i,j;
           for(i=5;i>=1;--i){
           System.out.println();
           for(j=0;j<i;++j){
                 System.out.print("*");
           };
        };
        System.out.println();
        };
  };