C language - multi-file compilation

1. constructor function to add two numbers together

06main.c

#include <stdio.h>
#include "06add.h"
int main() { 
    int val = add(3, 5); 
    printf("val是%d\n", val); 
    return 0; 
} 

06add.c

int add(int val, int val1) { 
    return val + val1; 
}  

06add.h

#ifndef     __06ADD_H__ 
#define     __06ADD_H__ 
int add(int, int);  
#endif      //__06ADD_H__ 

Compile way gcc 06main.c 06add.c

2. Compile function allows the user to get input from the keyboard in order not to be the main function calls, do not .h file statement

07main.c

/ * 
Call to get the main function 
* / 
#include <stdio.h> 
#include " 07get.h " 
int main () { 
    GET (); 
   the printf ( " number is obtained by D% \ n- " , Result); 
    return  0 ; 
}

07get.c

/ * 
Get an integer 
* / 
#include <stdio.h> 
#include " 07get.h " 
static  int Result = 0 ; // add the other files can not use static 
int SC () { 
     int Val = 0 ; 
    the printf ( " Please enter a number: " ); 
    Scanf ( " % D " , & Val); 
     return Val; 
} 
void  GET () { 
    Result = SC (); 
}
    

07get.h

__07GET_H__ #ifndef 
 #define      __07GET_H__ 
 extern  int Result; // function to obtain a value outside the 
void  GET ( void );  
 #endif       // __07GET_H__