Thread: Printing a hexagon using loops?

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I think I need to chang one of my loops but I can't figure it out.

You already have the shape though, if the loop was very wrong, the shape would be very wrong. I think you need to realize where the stars are in your shape so you can fix the code. You are supposed to print way more spaces than stars.

I guess the problem im having is printing the stars in the right spots. Could anyone help me out?

Well it's mostly a problem for the if(). Consider that the current character you need to print, whether it is a space or a star, means that you are either on a boundary line or you aren't. When you compare your loop variable to the boundaries you will know when you are supposed to print a star.

This is my new code. The top and bottom of the hexagram are the only part that is still missing. Can someone please help? I've been working on this for a very long time.

Code:

#include<stdio.h>
 
int main(void)
{
    int length, i=0, j=0, k, l;
    printf("Please enter the length for the sides of the hexagon:");   
    scanf("%d", &length);
      
    // for(i=0; i<length; i++)
    //{
    //     printf("*");
    //    }
    //

    for(i = 1, k=length, l=2*length-1; i<length; i++, k--, l++)
    {
    for(j = 0; j < 3*length; j++)
        {
        if(j==k || j==l)
            {
                printf("*");
        
            }
 
            else
                printf(" ");
        }
                printf("\n");
          
    }
             
    for(i = 0, k=1, l=3*length-2; i<length; i++, k++, l--)
        {
            for(j=0; j<3*length;j++)
            {
                if(j==k || j==l)
            {
                printf("*");
        
            }
 
            else
                printf(" ");
        }
                printf("\n");
        }
         
 
}

output:

The first and last lines are different and I think you wrote part of it before. It's when you begin or end the outer loops that the behavior is different.

Code:

if (j==k || j==l || (i == 1 && j >= k && j <= l)

Try that.
The other one the i will be length - 1

It's not likely to make a difference, and using puts() in particular is wrong, since the output would include a newline.

even a few cycles can make a visible difference but good point on puts(), putchar() is better idea for those few cycles

But the program is I/O bound anyway; it can only be as fast as it takes the computer to flush the output stream. That might not happen until the program closes, or maybe when an \n is pushed to stdout.