C :: How To Share Variable Value From One Source File To Other Header File

I wanted to share the value of a variable from Sender Program to Receive after program and want to calculate difference between send and receive. After studying Header file concept I program following three.

Now I am struck. How to to compile? I link all these file. I used following method:

Code:
gcc Sender.c -o Sender Sender.h
gcc Receiver.c -o Receiver Student.h

Then I run Sender and after that Receiver.I per my knowledge, Receiver should give difference but it gives error :

Code:
Receiver.c: In function "main":
Receiver.c:10:42: error: "Send" undeclared (first use in this function)
printf(" Total Receive is %d
",Receive-Send);

Code:
Sender.c
#include <stdio.h>
int Send ;
void main(){

[Code] ....