Question

write a program to print the following pattern of java
a
a a
a a a
a a a a
a a a a a
a a a a
a a a
a a
a

Answer 1

Pattern in Java, C++

Pattern Programs usually require some analysis. Here we see that we have 9 rows.

First 5 rows are increasing in length, next 4 are decreasing in length.

So we must run a loop 5 times, and then 4 times.

In each case, we must have an inner loop to print the elements.

For the increasing row length, we initialise a variable, say $i$ to 1 and run it in a for loop with end condition $i\leqslant 5$ and increment of $i++$. In each iteration of this loop, we run an inner loop $i$ times each to print "a".

For the decreasing row length, we initialise this $i$ to 4 and run it with end condition $i > 0$ and decrement of $i--$. Again, an inner loop must run $i$ times.

Here is a Java program which prints the pattern:

public class Pattern

{

   public static void main(String[] args)

   {

       for(int i=1;i<=5;i++)       //Loop runs 5 times for 5 rows for increasing row length

       {

           for(int j=0;j<i;j++)    //Inner Loop runs i times to print "a "

           {

               System.out.print("a ");

           }

           System.out.println();   //Entering a new line after each row

       }

       

       for(int i=4;i>0;i--)        //Loop runs 4 times for decreasing row length

       {

           for(int j=0;j<i;j++)    //Inner Loop runs i times to print "a "

           {

               System.out.print("a ");

           }

           System.out.println();   //Entering a new line after each row

       }

       

   }

}

__________________

Adding C++ Code on request:

#include <iostream>

using namespace std;

int main()

{

   for(int i=1;i<=5;i++)

   {

       for(int j=0;j<i;j++)

       {

           cout << "a ";

       }

       cout << endl;

   }

   

   for(int i=4;i>0;i--)

   {

       for(int j=0;j<i;j++)

       {

           cout << "a ";

       }

       cout << endl;

   }

   

   return 0;

}