Problems printing out this star shape - c

Question

While practicing I came across an assignment that required me to write a code which would print out the following shape:
https://postimg.cc/hJ7Hc72W
I tried a method where I had two for loops. I know the basic guidelines when it comes to printing star shapes but I simply can't complete this one. Whatever I do, I can just print out the left portion of the shape(the left pyramid) but the right one ends up being "warped".
#include <stdio.h>
#include <stdlib.h>
int main()
{
int n,i,j;
printf("Enter n: ");
scanf("%d", &n);
int length=2*n-1, width=2*n+1;
for(i=0; i<length; i++) {
for(j=0; j<width; j++) {
//The left side of the "||" separated condition prints the left pyramid,
// while the right side of the "||" should print out the right pyramid
if( (i>=j && i<=length-1-j) || (i<=j && i>=length-1-j) )
printf("*");
else printf(" ");
}
printf("\n");
}
return 0;
}
However, what I end up with is always this: https://postimg.cc/628SY4G1
Any idea where I might be wrong? Thanks so much!

Answer 1

Instead of looping over everywhere and filtering to determine which character to print (as you have noticed, this is surprisingly tricky to get right), break the figure down into sections.
Start with printing a single line, width wide and with stars stars.
This can be done with three loops:
void print_line(int width, int stars)
{
for (int i = 0; i < stars; i++)
printf("*");
for (int i = 0; i < width-2*stars; i++)
printf(" ");
for (int i = 0; i < stars; i++)
printf("*");
printf("\n");
}
Then write a loop for the top n-1 lines and a loop for the bottom n-1 lines, with one full-width line inbetween:
int width = 2*n+1;
for (int i = 1; i <= n-1; i++)
print_line(width, i);
print_line(width, n);
for (int i = n-1; i >= 1; i--)
print_line(width, i);

Answer 2

This way works:
#include <stdio.h>
int main()
{
int n,i,j,k;
printf("Enter n: ");
scanf("%d", &n);
int length=2*n-1;
int reqd_no_of_stars;
for(i=0; i<=length; i++)
{
if(length+1-i<i)
{
reqd_no_of_stars=length+1-i;
}
else
{
reqd_no_of_stars=i;
}
for(k=0; k<reqd_no_of_stars; k++)
printf("*");//print left set of stars equal to the number of reqd_no_of_stars
for(k=0; k<(2*n+1)-2*reqd_no_of_stars; k++)
printf(" ");//print required spaces=total_width-required_width_for_stars=((2*n+1)-2*reqd_no_of_stars) in between stars of both sides
for(k=0; k<reqd_no_of_stars; k++)
printf("*");//print right set of stars equal to the number of reqd_no_of_stars
printf("\n");
}
return 0;
}

Answer 3

If you structure your code, you'll have very little problem in painting the ties:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static const char AST[] = "**********";
static const char BLK[] = " ";
void paint_line(const char *s, int n)
{
int l = strlen(s);
while (n >= l) {
fputs(s, stdout);
n -= l;
}
/* n < l */
if (n > 0)
printf("%.*s", n, s);
}
void paint_tie(int n)
{
int row;
for(row = 1; row <= n; row++) {
paint_line(AST, row);
paint_line(BLK, 2*(n-row) + 1);
paint_line(AST, row);
printf("\n");
}
for (row = n-1; row > 0; row--) {
paint_line(AST, row);
paint_line(BLK, 2*(n-row) + 1);
paint_line(AST, row);
printf("\n");
}
}
int main(int argc, char **argv)
{
int i;
for (i = 1; i < argc; i++) {
int n = atoi(argv[i]);
paint_tie(n);
}
}
The routine main() just extracts the sizes of the ties from the command line. I've not included code to check if atoi(3) returns the proper value, but for sure you can complete the exercise.
The routine paint_tie() prints one tie, it just prints the lines with the number of characters that are requested, growing up to n, then waning to zero again.
Finally, the routine paint_line just paints a sequence of chars, selected from a string passed as a parameter. It prints as many complete strings (just trying to be efficient) using the function fputs(3) until there's no more place for a full string, it then uses (only once, as that's expensive) the %.*s format, which allows me to get the first part of the string, up to the trailing characters that are not multiple of the string length. You can download the example here.
BTW, why do you ask this? Is it a homework exercise, or you are just practicing (as you say in your question) Any case, you are doing bad just asking here, as you are not exercising yourself. Why do you auto ask to do an exercise, and then come here to look for the answer? Cannot understand.