Respuesta :
Answer:
Hi There was small mistake. It is working fine for me. When you run from command line - use LoopPattern, not looppatern
import java.util.Scanner;
public class Looppattern {
 public static void main(String[] args) {
   Scanner sc = new Scanner(System.in);
   System.out.println("Enter how man levels you need: ");
   int levels = sc.nextInt();
   System.out.println("\n---------------Pattern A-----------------\n");
   for (int p = 1; p <= levels; p++) {
     for (int k = 1; k <= p; k++) { // increasing each level printing
       System.out.print(k);
     }
     System.out.println();
   }
   System.out.println("\n---------------Pattern B-----------------\n");
   int r = levels;
   for (int p = 1; p <= levels; p++) {
     for (int k = 1; k <= r; k++) {
       System.out.print(k);
     }
     r--; // decreasing levels
     System.out.println();
   }
   System.out.println("\n---------------Pattern C-----------------\n");
   for (int p = 1; p <= levels; p++) { // here incresing
     for (int k = p; k > 0; k--) { // and here decreasing pattern to
                     // achieve our required pattern
       System.out.print(k);
     }
     System.out.println();
   }
   System.out.println("\n---------------Pattern D-----------------\n");
   r = levels;
   for (int p = 1; p <= levels; p++) {
     for (int k = 1; k <= r; k++) {
       System.out.print(k);
     }
     r--; // decreasing levels
     System.out.println();
   }
 }
}
Explanation: