int main()
{
int numb,j,space;

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

    printf("\n");

    while(numb<=1){
        printf("Enter another number:");
        scanf("%d", &numb);
    }


    if(numb>20) numb=20;///sets number greater than 20
    for(j = 1; j <= numb; j++)
    {
        printf("*");
        for(space = 1; space < j; space++)
        {
            printf(" ");
        }
        printf("*\n");
    }


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


    return 0;
}