I use printf & scanf in the program below.
I enter a value and then the value is used in the formulas.

But all the program does is printing
enter length :
and although I can put some number... the program does nothing.
No error, no warning, nothing...
It just stops there.

So I think there's something wrong aobut the scanf...
Can someone help me?

Code:
#include <stdio.h>
#include <math.h>
#include <stdlib.h>

#define PI 3.14
#define g 9.807

int main(void)
{
    double period, length; 
        
    printf("enter length : ");
    scanf("%lf\n", &length);
        
    period=2*PI*sqrt(length/g);
    length=(period*period*g)/(4*PI*PI);
    
    printf("period is %g\n", period);
    printf("length is %g\n", length);        
    
    getch();
    return 0;
    }