[C] Header file, Main.c, Rink

/*------------------------------------------------------------------------------------------

@ Pratice C laguage

Author           : SAM

Created          : 30-03-2017

Modified         : 30-03-2017

Language/ver     : C in MSVS2015

Description     : Practice

KEYWORD : Caculator header file

------------------------------------------------------------------------------------------*/

extern int cal_num;

double add(double a, double b);

double minus(double a, double b);

double multiple(double a, double b);

double divide(double a, double b);

/*------------------------------------------------------------------------------------------

@ Pratice C laguage

Author           : SAM

Created          : 30-03-2017

Modified         : 30-03-2017

Language/ver     : C in MSVS2015

Description     : Practice

KEYWORD : calculator.c

------------------------------------------------------------------------------------------*/

int cal_num = 0;

double add(double a, double b) {

cal_num++;

return a + b;

}

double minus(double a, double b) {

cal_num++;

return a - b;

}

double multiple (double a, double b) {

cal_num++;

return a*b;

}

double divide(double a, double b) {

cal_num++;

return a/b;

}

/*------------------------------------------------------------------------------------------

@ Pratice C laguage

Author           : SAM

Created          : 30-03-2017

Modified         : 30-03-2017

Language/ver     : C in MSVS2015

Description     : Practice

KEYWORD : main.c

------------------------------------------------------------------------------------------*/

#include<stdio.h>

#include "calculator.h"

int main() {

double a = 10.2;

double b = 2.1;

printf(" + : %f\n", add(a, b));

printf(" - : %f\n", minus(a, b));

printf(" * : %f\n", multiple(a, b));

printf(" / : %f\n", divide(a, b));

printf("Total calculator num : %d\n", cal_num);

return 0;

}

1. header file : 외부 변수 불러옴, 함수 정의문 작성

2. 서브파일 : 변수 선언 및 초기화, 함수 바디 작성

3. 메인파일 : 헤더파일 불러옴, 바로 함수 사용가능