SmileBD

*****
  ****
    ***
      **
        *
        *
      **
    ***
  ****
*****

#include <stdio.h>
int main()
{
    int i, j, n;
    //Reads number of rows from user
    printf("Enter value of n : ");
    scanf("%d", &n);
    //Prints the upper part of the arrow
    for(i=1; i<=n; i++)
    {
        //Prints trailing (2*rownumber-2) spaces
        for(j=1; j<=(2*i-2); j++)
        {
            printf(" ");
        }
        //Prints inverted right triangle star pattern
        for(j=i; j<=n; j++)
        {
            printf("*");
        }
        printf("\n");
    }
    //Prints lower part of the arrow
    for(i=1; i<=n; i++)
    {
        //Prints trailing (2*n - 2*rownumber) spaces
        for(j=1; j<=(2*n - 2*i); j++)
        {
            printf(" ");
        }
        //Prints simple right triangle star pattern
        for(j=1; j<=i; j++)
        {
            printf("*");
        }
        printf("\n");
    }
    return 0;
}

Enter value of n : 5

*****
  ****
    ***
      **
        *
        *
      **
    ***
  ****
*****