1. make工具的引入

1. 用gcc编译 

book@100ask:~/arm/ch01$ ls
calcu.c  calcu.h  input.c  input.h  main.c

book@100ask:~/arm/ch01$ cat calcu.c
#include "calcu.h"

int calcu(int a,int b)
{
	return(a + b);
}

book@100ask:~/arm/ch01$ cat calcu.h
#ifndef _CALCU_H
#define _CALCU_H

int calcu(int a,int b);
#endif

book@100ask:~/arm/ch01$ cat input.c
#include <stdio.h>
#include "input.h"

void input_int(int *a, int *b);
{
	printf("input two num:");
	scanf("%d %d",a,b);
	printf("\r\n");
}

book@100ask:~/arm/ch01$ cat input.h
#ifdef  _INPUT_H
#define _INPUT_H

void input_int(int *a, int *b);
#endif

book@100ask:~/arm/ch01$ cat main.c
#include <stdio.h>
#include "input.h"
#include "calcu.h"

int main(int argc, char *argv[])
{
	int a, b, num;

	input_int(&a, &b);
	num = calcu(a