I am defining a variable n using scanf in my main function. will the rest of my program know it?

I am solving an equation and have a square root part of my function that sends back the square root value to my main function.

Code:

double getSquareRoot ( void );
int main(void)
{
double n_factorial; // powers multipled by the solved square root
printf("ESTIMATE A FACTORIAL NUMBER\n");
printf("This program was written by %s.\n", PROGRAMMER_NAME);
printf("Please enter a positive integer: "):
scanf("%lf", &n);
sqrt_partial = (2.0 * n) + (1.0 + 3.0);
sqrt_solved = getSquareRoot( );
n_factorial = pow(n,n) * exp(-n) * sqrt_solved;
printf("%.0f! equals approximately %.5f \n", n, n_factorial);
return EXIT_SUCCESS;
}
double getSquareRoot (void)
{
double n; // User defines the factorial
double sqrt_partial;
double sqrt_solved;
printf("Please enter a positive integer: "):
scanf("%lf", &n);
sqrt_partial = (2.0 * n) + (1.0 / 3.0);
sqrt_solved = sqrt(sqrt_partial * PI);
retun sqrt_solved;
}