Printing Pattern Using Nested Loop In BlueJ

While doing pattern using any program, we have to use nested loop. Here one point to be kept in mind that while using nested loops to form pattern, outer loop controls the rows and the inner loop controls the columns. The designing part of any pattern is solely dependant on inner loop. So the printing part job is always done by the inner loop. After studying the pattern, execute the outer loop to generate rows. But the main job is done by the inner loop. So you have to think very deeply about the inner loop designing.

 Few program on pattern are as follows:

 

123454321

1234 4321

123   321

12     21

1       1

class pt1

{

int i,j,k,m,x;

void show()

{

for(i=0;i< 5;i++)

{

x=1;

for(j=i;j< 5;j++)

System.out.print(x++);

for(k=0;k<  i; k++)

System.out.print(" ");

x=x-1;

for(m=i;m< 5;m++)

System.out.print(x--);

System.out.println();

}

}

public static void main(String args[])

{

pt1 ob=new pt1();

ob.show();

}

}

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This above pattern is displayed using three inner loops inside the outer loop. Outer loop as usual generates the rows. First inner loop displays one digit more than that of the third inner loop. The middle inner loop displays the blank spaces of the pattern. Each time the first inner loop starts with '1' and go on incrementing. When the control leaves the first inner loop the middle inner loop catches the control. Again the third inner loop starts from a value less than 2 of the last value of the loop control variable of first inner loop.

Next program on pattern

1 1

12 3

123 6

1234 10

12345 15

  

class pt1

{

int i,j,k,m,x;

void show()

{

x=0;

for(i=1;i< =5;i++)

{

for(j=1;j< =i;j++)

{

System.out.print(j);

}

x=x+i;

System.out.println(" "+x);

 }

 }

public static void main(String args[])

{

pt1 ob=new pt1();

ob.show();

}

}

 This above program is a typical pattern where the inner loop iteration is not fixed. As the outer loop executes, the inner loop execution increases. At the end of execution of the inner loop each time it prints the sum of the digits of that row with a space. As the inner execution increases after each iteration, outer loop control variable is set in the conditional statement of the inner loop. As the control leaves the inner loop, it prints the sum of the digits.

Next program on pattern

1

1 2 1

1 2 3 2 1

1 2 3 4 3 2 1

  

class pt1

{

int i,j,k,m,x;

void show()

{

for(i=0;i< 4;i++)

{

for(j=i;j< 3;j++)

{

if(j==0)

System.out.print("  ");

else

System.out.print(" ");

}

x=1;

for(k=0;k< =i*2;k++)

{

if(k%2==0)

System.out.print(x++);

else

System.out.print(" ");

}

System.out.print(" ");

x=x-2;

for(m=0; m < i*2; m++)

{

if(m%2==0)

System.out.print(x--);

else

System.out.print(" ");

}

System.out.println();

}

}

public static void main(String args[])

{

pt1 ob=new pt1();

ob.show();

}

}

OR

class pt1

{

int i,j,k,m,x;

void show()

{

for(i=0;i< 4;i++)

{

for(j=i;j< 3;j++)

{

System.out.print(" ");

}

x=1;

for(k=0;k< =i;k++)

{

System.out.print(x++);

 }

x=x-2;

for(m=0; m< i;m++)

{

 System.out.print(x--);

}

System.out.println();

}

}

public static void main(String args[])

{

pt1 ob=new pt1();

ob.show();

}

}

 *******

*****

***

 *

***

*****

*******

Also Read: Computer Teacher at Burdwan

class pt1

{

int i,j,k,m,x;

void show()

{

x=7;

for(i=0;i< 4;i++)

{

for(j=0; j < i;j++)

System.out.print(" ");

 for(k=0; k< x;k++)

System.out.print("*");

x=x-2;

for(j=0; j< i;j++)

System.out.print(" ");

System.out.println();

}

 x=1;

for(i=0;i< 4;i++)

{

for(j=i+1;j< 4;j++)

System.out.print(" ");

 for(k=0; k< x;k++)

System.out.print("*");

x=x+2;

for(j=i+1;j< 4;j++)

System.out.print(" ");

System.out.println();

}

 }

public static void main(String args[])

{

pt1 ob=new pt1();

ob.show();

}

}

In this program also, inner loop creates this pattern.  This pattern consists of two nested loops and within each outer loop, the first inner loop prints space at the left side and the second inner loop prints the star symbols. After each iterations, the inner loop execution decreases. The first nested loop prints the pattern upto the single star symbol. The other nested loop prints the lower part of the program. Here the inner loop execution increases after each iterations.

  

This site is on Bluej for icse schools. If you have any doubt in any program, pl. feel free to put your comments. I am here to clear your doubts.

Related Post: BlueJ Programs On Pattern