diamond star wall pattern with abs() and longest row v1.c

/*
 diamond star wall pattern with abs() and longest row v1.c

 Enter the number of stars in the longest row of diamond, ns.

 The number of stars in the longest row of diamond is same as
 the number of rows of the upper triangle of diamond.

 Diamond will have 2*ns-1 raws.

 We enter maximum number of stars in single row,
 then we draw such a diamond.

ns = 5

----*-
---*-*-
--*-*-*-
-*-*-*-*-
*-*-*-*-*-
-*-*-*-*-
--*-*-*-
---*-*-
----*-

row  spaces,j   *          i

 0.     4       1         -4
 1.     3       2         -3
 2.     2       3         -2
 3.     1       4         -1
 4.     0       5          0
 5.     1       4          1
 6.     2       3          2
 7.     3       2          3
 8.     4       1          4

*/

#include "stdio.h"

int main(void)
{
/*
    i   counter in loop for rows
    j   counter in print loops
    ns  number of rows of the upper triangle of diamond
        or number of stars in the longest row of diamond
*/
    int i, j, ns;

    printf("\n the number of stars in the longest row of diamond, ns = ");
    scanf("%d", &ns);                       // try 5, 6 or 30

    printf("\n");

    for (i = -ns + 1; i < ns; i++)          // loop for rows
    {
//      printf("%*s", abs(i), "");          // this line or for (j = 0; j < abs(i); j++)

        for (j = 0; j < abs(i); j++)        // print "-"
            printf("-");

        for (j = 0; j < ns - abs(i); j++)   // print "*-"
            printf("*-");

        printf("\n");                       // new row
    }

    return 0;
}