Rhombus Pattern

/*
    1 1
   2   2
  3     3
 4       4
5         5
 4       4
  3     3
   2   2
    1 1
*/

#include<stdio.h>

int main()
{
    int num, r, c, sp, n;

    printf("Enter maximum number : ");
    scanf("%d", &num);

    for (r = 1; r <= num; r++)
    {
        for (sp = num - r; sp >= 1; sp--)
            printf(" ");

        printf("%d", r);

        for (sp = r * 2; sp > 1; sp--)
            printf(" ");

        printf("%d", r);
        printf("\n");
    }

    for (r = 1, n = num - 1; r < num; r++, n--)
    {
        for (sp = r; sp >= 1; sp--)
            printf(" ");

        printf("%d", n);

        for (sp = n * 2; sp > 1; sp--)
            printf(" ");

        printf("%d", n);
        printf("\n");
    }

    return 0;
}

OUTPUT

Enter maximum number : 5
    1 1
   2   2
  3     3
 4       4
5         5
 4       4
  3     3
   2   2
    1 1