C Program to Generate Diamond Pattern Using Stars

#include<stdio.h>

int main()
{
    int i, n, j;

    printf("Enter number of lines: ");
    scanf("%d", &n);

    /* Upper part of diamond */
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=n-i;j++)
        {
            printf(" ");
        }
        for(j=1;j<=2*i-1;j++)
        {
            printf("*");
        }
        printf("\n");
    }
    /* Lower part of diamond patter */

    for(i=n-1;i>=1;i--)
    {
        for(j=1;j<=n-i;j++)
        {
            printf(" ");
        }
        for(j=1;j<=2*i-1;j++)
        {
            printf("*");
        }
        printf("\n");
    }

    return 0;
}

Output 

Enter number of lines: 10

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