Programming abstractions in C阅读笔记p111-p113: boilerplate

《Programming Abstractions In C》学习第47天，p111-p113，总结如下：

一、技术总结 1.boilerplate

/*
 * File: random.h
 * Version: 1.0
 * Last modified on Fri Jul 22 16:44:36 1994 by eroberts
 * -----------------------------------------------------
 * This interface provides several functions for generating
 * pseudo-random numbers.
 */

#ifndef _random_h
#define _random_h

#include "genlib.h"
#include <stdlib.h>

/*
 * Constant: RAND_MAX
 * ------------------
 * Unfortunately, several libraries that supposedly conform to
 * the ANSI standard do not define RAND_MAX in <stdlib.h>.  To
 * reduce portability problems, this interface defines RAND_MAX
 * to be the largest positive integer if it is undefined.
 */

#ifndef RAND_MAX
#  define RAND_MAX ((int) ((unsigned) ~0 >> 1))
#endif

/*
 * Function: Randomize
 * Usage: Randomize();
 * -------------------
 * This function sets the random seed so that the random sequence
 * is unpredictable.  During the debugging phase, it is best not
 * to call this function, so that program behavior is repeatable.
 */

void Randomize(void);

/*
 * Function: RandomInteger
 * Usage: n = RandomInteger(low, high);
 * ------------------------------------
 * This function returns a random integer in the range low to high,
 * inclusive.
 */

int RandomInteger(int low, int high);

/*
 * Function: RandomReal
 * Usage: d = RandomReal(low, high);
 * ---------------------------------
 * This function returns a random real number in the half-open
 * interval [low .. high), meaning that the result is always
 * greater than or equal to low but strictly less than high.
 */

double RandomReal(double low, double high);

/*
 * Function: RandomChance
 * Usage: if (RandomChance(p)) . . .
 * ---------------------------------
 * The RandomChance function returns TRUE with the probability
 * indicated by p, which should be a floating-point number between
 * 0 (meaning never) and 1 (meaning always).  For example, calling
 * RandomChance(.30) returns TRUE 30 percent of the time.
 */

bool RandomChance(double p);

#endif

p113，These three lines are often referred to as interface boilerplate。boilerplate这个词会在计算机相关的教材中会经常看到，英文的意思是：“text that can be copied and used in computer program，with only small changes.”(模板)，之所以叫模板，是因为在每个头文件中都有这三句。这个单词不难理解，关键是通过此次的教材对这个单词有一个具体的、形象的记录，当提到这个单词，就知道具体指的是什么。

二、英语总结

1.roll a die一句里面的die是什么意思？ 答：die: n.a small cube with a different number of spots on each side.(骰子)，所以roll a die的就是"掷骰子"。

2.along with语法

答：along with在表示伴随、以及或连同等意思时，两者之间无先后顺序，可能在前也可能在后。这点与follow不同。示例：For each of these functions, the interface contains one-line prototype along with a comment that describe the purpose of the function from the perspective of clients.

3.up to 语法 答：原文：The line:

#ifndef _random_h

cause the compiler to skip any text up to the #endif line if the the symbol _random_h has been previously defined。

up to短语主要有两种用法：

(1)adv. used to say that sth is less than or equal to but not more than a stated value。

(2)adv. until。

都表示的是“程度”，而不是“方向”。

三、参考资料

1.编程

1)Eric S.Roberts，《Programming Abstractions in C》：https://book.douban.com/subject/2003414

2.英语

1)Etymology Dictionary：https://www.etymonline.com

2)Cambridage Dictionary：https://dictionary.cambridge.org

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