Methodology to crack pattern problems like constructing a pyramid of stars or diamond made up of stars.

Have you wondered how to crack problems like generating patterns from C code or Java code ?? Here, I am presenting a methodology to crack simple pattern problems.

Write an algorithm to generate following pattern:
     *
  *     *
*          *
  *     *
      *

for n=any odd number say 5.

To understand the behavior of pattern put them inside grid a follows:

0

1

2

3

4

0			*
1		*		*
2	*				*
3		*		*
4			*

Now we will check what trend above pattern is following. On close observation we find out that

upper left edge of pattern follows :
print * if  i<=2 and j<=2 and i+j=2

upper right edge of pattern follows :
print * if  i<=2 and j>=2 and j-i=2

lower left edge of pattern follows :
print * if  i>=2 and j<=2 and i-j=2

upper left edge of pattern follows :
print * if  i>=2 and j>=2 and i+j=6

Now following code-snippets can be written to generate above pattern:


for(j=0;j<n;j++)
{
for(i=0;i<n;i++)
{
if((i<=n/2 && j<=n/2 && i+j==n/2)||(i<=n/2 && j>=n/2 && j-i==n/2)||(i>=n/2 && j<=n/2 && i-j==n/2)||(i>=n/2&& j>=n/2 && i+j==((n-1)/2)*3))
{
printf("*");
}
else
printf(" ");
}
printf("\n");
}



Hope you have understood essence of pattern generation. As a assignment, you can generate following pattern :

0			*
1		*	*	*
2	*	*	*	*	*