userchoicepatt.java

import java.util.*;
class patt1
{
    void pat1(){
        int i,j, n=5;
        for(i=0;i<=n;i++)
        {
            for(j=0;j<i;j++)
            {
                System.out.print("* ");
            }
            System.out.println();
        }
    }
}
class patt2 {
     void pat2() {
         int i,j, n=5;
        for(i=0;i<=n;i++)
        {
            for(j=i;j<n;j++)
            {
                System.out.print(" ");
            }
            for(j=0;j<i;j++)
            {
                System.out.print("* ");
            }
            System.out.println();
        }
    }
}
 class patt3{
    void pat3() {
         int i,k,j,n=5;
           for (i= 0; i<= n-1 ; i++)
            {
                for (j=0; j<i; j++)
                {
                System.out.print(" ");
                }
                for (k=i; k<=n-1; k++)
                {
                System.out.print("*" + " ");
                }
                System.out.println("");
            }
            for (i= n-1; i>= 0; i--)
            {
                for (j=0; j<i; j++)
                {
                System.out.print(" ");
                }
                for (k=i; k<=n-1; k++)
                {
                System.out.print("*" + " ");
                }
            System.out.println("");
            }
    }
}

class menu{
public static void main(String args[])
{
    Scanner in= new Scanner(System.in);
    System.out.println("1>right angle triangle star pattern\n2>pyramind star pattern\n3>hour glass star pattern\nenter your choice:");
    int ch=in.nextInt();
    switch(ch)
    {
        case 1:
        patt1 p=new patt1();
        p.pat1();
        break;
        case 2:
        patt2 p1=new patt2();
        p1.pat2();
        break;
        case 3:
        patt3 p2=new patt3();
        p2.pat3();
        break;
        default:
        System.out.println("invalid choice");
    }
}
}