May 2014

Thursday, 29 May 2014

Print Star( * ) Patterns

Here are some tricks to print * pattern

If you can print pattern like this then you are genius

NOTE : Now all you need to print any other pattern is just satisfy a condition before printing *

Java code to generate above pattern is given below.

save it with name Pattern.java

package com.trickyjava.pattern;

public class Pattern {

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

}

In above pattern first loop for (int i = 1; i <= 5; i++) used for rows
and second loop for (int j = 1; j <= 5; j++) is used for columns

Now if we want to print pattern like this

for this we need to put a condition before printing *

So now we will learn how to make condition to print pattern

Here is explanation for the above pattern

NOTE : we will make condition based on ( j + i ) and ( j - i ) for any pattern.

Now java code to print the above pattern is

package com.trickyjava.pattern;

public class Pattern {

 public static void main(String[] args) {
  for (int i = 1; i <= 5; i++) {
   for (int j = 1; j <= 5; j++) {
    if (i + j <= 6) {             
     System.out.print(" * ");
    } else {                        
     System.out.print("   ");
    }                               
   }
   System.out.println();
  }
 }

}

Here are some other patterns you can try.

Change the condition for the required pattern

Some more patterns

Change no. of rows or columns to print required pattern

Tuesday, 27 May 2014

13:30

Stack Implementation without using Array

Here is simple code to implement Stack without using array.

This is Stack.java

package com.trickyjava;

public class Stack<T> {
     private StackElement<T> top;

     public T pop() throws Exception {
          if (null == top) {
             throw new Exception("No element in stack");
          }
          T element = top.getElement();
          top = top.getPrevious();
          return element;
     }

     public void push(T element) {
          if (null == top) {
             top = new StackElement<T>(null, element);
             return;
          }
          top = new StackElement<T>(top, element);
     }

     public void empty() {
          top = null;
     }
  
     public boolean hasMoreElements() {
          return null != top;
     }
  
     private class StackElement<T> {
  
          private StackElement<T> previous;
          private T element;
    
          public StackElement(StackElement<T> previous, T element) {
             this.previous = previous;
             this.element = element;
          }
    
          public T getElement() {
             return element;
          }
    
          public StackElement<T> getPrevious() {
             return previous;
          }
    }
}

This is code how you will use it.
This is Application.java

package com.trickyjava;

public class Application {

     public static void main(String[] args) {
        Stack<String> stack = new Stack<>();
        stack.push("This");
        stack.push("is");
        stack.push("stack");
        stack.push("implementation");
        stack.push("without");
        stack.push("using");
        stack.push("array");

        while (stack.hasMoreElements()) {
           try {
              System.out.println(stack.pop());
           } catch (Exception e) {
              e.printStackTrace();
           }
        }
    }

}

This is Output

array
using
without
implementation
stack
is
This

13:07

Welcome to www.TrickyJava.com

Hi This is my very first post on www.TrickyJava.com . So basically this blog is for tricky codes in java and java code related problems and solutions. Thanks for support and contribution.

Tricky {Java}

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