/*************************************************************************

     > File Name: main.c

     > Author:

     > Mail:

     > Created Time: Tue 25 Jul 2017 10:40:22 AM CST

  ************************************************************************/

 #include<stdio.h>

 #include"add_sub.h"

 int main()

 {

     printf(" 2 + 3 = %d\n", add(, ));

     printf(" 2 - 3 = %d\n", sub(, ));

     return ;

 }

 /*************************************************************************

     > File Name: add.c

     > Author:

     > Mail:

     > Created Time: Tue 25 Jul 2017 10:36:26 AM CST

  ************************************************************************/

 #include "add_sub.h"

 int add(int a, int b)

 {

     return a + b;

 }  

 /*************************************************************************

     > File Name: sub.c

     > Author:

     > Mail:

     > Created Time: Tue 25 Jul 2017 10:37:54 AM CST

  ************************************************************************/

 #include "add_sub.h"

 int sub(int a, int b)

 {

     return a - b;

 }  

 /*************************************************************************

     > File Name: add_sub.h

     > Author:

     > Mail:

     > Created Time: Tue 25 Jul 2017 10:38:53 AM CST

  ************************************************************************/

 #ifndef _ADD_SUB_H

 #define _ADD_SUB_H

 int add(int a, int b);

 int sub(int a, int b);

 #endif

 main: add.o sub.o main.o

       gcc add.o sub.o main.o -o main  

 add.o: add.c add_sub.h

      gcc -c add.c -o add.o  

 sub.o: sub.c add_sub.h

      gcc -c sub.c -o sub.o 

 main.o:main.c add_sub.h

      gcc -c main.c -o main.o

 clean:

 　　rm -rf *.o main