Pattern Program Concept

Let us suppose we have to draw a pattern like this-

***1***
**121**
*12321*
1234321


Whatever be the pattern the method remains same.
Let us take an even complex pattern -

1

  121

 12321

1234321

 12321

  121

   1




All patterns can be grouped into number of triangles as shown above.


For

***1***
**121**
*12321*
1234321    pattern we have 4 sub triangles

1.

***
**
*

2.

      1
    12
  123
1234


3.


1
21
321

4.

***
**
*


We will write a master for loop for 4 times i.e equal to the number of rows we have to print and insite that we will run for loops 4 times for each triangle.

If the pyramid becomes inverted after half then we will have to have 2 mater for loops.



#include<stdio.h>

int main()
{

for (int i = 1; i <= 4; i++)  //for 4 horizontal lines
{

        for (int j = 4; j-i > 0; j--)   //as we go down we have to print one star lesser
printf("*");

       for (int k = 1; k <= i; k++)  //as we go down we have to print one more digit in increasing order
printf("%d", k);

for (int m = i; m > 1; m--) /*except for first line we have to print one digit less than the line number */'
printf("%d", m-1);

for (int l = 4; l - i >= 1; l--)
printf("*");

printf("\n");

}

return 0;

}

Fibonacci Series

It is a series of numbers such that the first number is 0, second is 1 and from thereon every number is a sum of previous two numbers.
0 1 1 2 3 5.....

The concept can be extended for negative numbers also  -8, 5, -3, 2, -1, 1, 0, 1, 1, 2, 3, 5, 8,
For the sake of simplicity we re considering non negative sequence only.



#include<stdio.h>

int main()
{
int n;

printf("enter the number of fibonacci numbers you want to enter \n \n");
scanf_s("%d", &n);

if (n <= 0)
printf("not valid or negative sequence \n");

else if (n == 1)
printf("0 \n");
else if(n==2)
printf("0 1\n");

else
{
int a2 = 0;
   int a1 = 1;
int newnum;
printf("0 \n1\n");
for (int i = 2; i < n; i++)
{
newnum = a2 + a1;
printf("%d \n", newnum);
a2 = a1;
a1 = newnum;
}


}

return 0;

}


O/P-

Inverted Pyramid of Characters

Let's try to write a program which will print an inverted pyramid of character like this if we give input as 4

ABCDCBA
   ABCBA
      ABA
         A

#include<stdio.h>

int main()

{

 int rows,i,j,k;

printf("enter the number of rows you want to print \n");
scanf("%d",&rows);

for(i=0;i<rows;i++)
{
  
  
    for(j=0;j<i;j++)
    {
        printf(" ");
    }
  
    for(k=0;k<((rows-1)-i);k++)
    {
        printf("%c ",(65+k));
    }
  
    for(;k>=0;k--)
    {
    printf("%c ",(65+k));
    }
    printf("\n");
}

Simple Star Pattern Program

 Lets write a program to print this pattern.

    *
   ***
  *****
 *******
*********

This is a very basic program and it will test you understanding of loops. 

#include<stdio.h>

int main()

{

 int rows,i,j,k,l;

printf("enter the number of rows you would like to see in the pyramid \n");

scanf("%d",&rows);


for( i=0;i<rows;i++)    //print each row one by one

{

for( j=0;j<(rows-i);j++)   //to print initial blanks

{

printf(" ");

}

for( k=0;k<(2*i+1);k++)      // to print stars

{

printf("*");

}


printf("\n");
}

return 0;
}


NB: we don't need to print the later blank spaces as it will be there automatically when adjusted