how print triangles in c

1#include <stdio.h>
2int main() {
3   int rows, i, j, space;
4   printf("Enter the number of rows: ");
5   scanf("%d", &rows);
6   for (i = rows; i >= 1; --i) {
7      for (space = 0; space < rows - i; ++space)
8         printf("  ");
9      for (j = i; j <= 2 * i - 1; ++j)
10         printf("* ");
11      for (j = 0; j < i - 1; ++j)
12         printf("* ");
13      printf("\n");
14   }
15   return 0;
16}
17

1#include <stdio.h>
2int main() {
3   int rows, coef = 1, space, i, j;
4   printf("Enter the number of rows: ");
5   scanf("%d", &rows);
6   for (i = 0; i < rows; i++) {
7      for (space = 1; space <= rows - i; space++)
8         printf("  ");
9      for (j = 0; j <= i; j++) {
10         if (j == 0 || i == 0)
11            coef = 1;
12         else
13            coef = coef * (i - j + 1) / j;
14         printf("%4d", coef);
15      }
16      printf("\n");
17   }
18   return 0;
19}
20

1           1
2         1   1
3       1   2   1
4     1   3   3    1
5   1  4    6   4   1
6 1  5   10   10  5   1
7

1* * * * * * * * *
2  * * * * * * *
3    * * * * *
4      * * *
5        *
6