C 语言概述

编写一个简单的 C 程序

#include <stdio.h>

int main(void)
{
  int num;                  /* define a variable called num */
  num = 1;                  /* assign a value to num */
  printf("I am a simple "); /* use the printf() function */
  printf("computer.\n");
  printf("My favorite number is %d because it is first.\n", num);
  return 0;
}

//* 一个文件包含2个C函数 */
#include <stdio.h>

void butler(void); /* ANSI/ISO C函数原型 */

int main(void)
{
  printf("I will summon the butler function.\n");
  butler();
  printf("Yes. Bring me some tea and writeable DVDs.\n");
  return 0;
}

void butler(void) /* 函数定义 */
{
  printf("You rang, sir?\n");
}

关键字和保留标识符