C/C++ 学习笔记[03].去掉C风格的注释
网上搜索了一大堆去掉/*和*/之间注释的代码,就像<The C Programming Language>练习1-23里有人说的一样
大部分都会被以下的程序broken,这个功能看起来简单,实际上很有难度.网上实现的代码,除了我找到的一个用文件指针实现的没有问题外,其余的都存在各种bug,不信的话就用以下的程序测试一下:-),当然这个程序也不够完善.
还是有限状态自动机实现起来更严谨也容易理解得多:
/* krx123tp.c - a test program to serve as input to krx123*.c
*
* This is a shameless copy of Ben Pfaff's solution, to which I have
* added a few extra statements to further test the candidate programs
* for this exercise. As Ben says, this program already contains lots
* of examples of comments and not-quite-comments. I've just made it
* a little tougher.
*
*/
/* K&R2 1-23: Write a program to remove all comments from a C program.
Don't forget to handle quoted strings and character constants
properly. C comments do not nest.
This solution does not deal with other special cases, such as
trigraphs, line continuation with \, or <> quoting on #include,
since these aren't mentioned up 'til then in K&R2. Perhaps this is
cheating.
Note that this program contains both comments and quoted strings of
text that looks like comments, so running it on itself is a
reasonable test. It also contains examples of a comment that ends
in a star and a comment preceded by a slash. Note that the latter
will break C99 compilers and C89 compilers with // comment
extensions.
Interface: The C source file is read from stdin and the
comment-less output is written to stdout. **/
#include <stdio.h>
int
main(void)
{
/* State machine's current state. */
enum {
PROGRAM,
SLASH,
COMMENT,
STAR,
QUOTE,
LITERAL
} state;
/* If state == QUOTE, then ' or ". Otherwise, undefined. */
int quote;
state = PROGRAM;
for (;;) {
int c = getchar();
if (c == EOF)
相关文档：
假设有char a[2];
如要把a转换为int值。应是如下写法int b=*(int *)a;
即，先把指针a 转换为一个int指针，然后再此基础上取值。
但是另一种写法 int b=(int)(*a);是不对的，*a 取a的内存单元内容，因为现在a是char指针，所以只会取a[1]中内容，最大为255. 这里要说明的是，在把char或byte数组转换为其他类型的值时，要先 ......
c库函数详解——assert
函数名: assert
功 能: 测试一个条件并可能使程序终止
用 法: void assert(int test);
程序例:
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
struct ITEM {
int key;
int value;
};
/* add item to ......
今天看K&R的书的时候顺便温习了C的另一重要数据结构bit-fields，我想bit-fields在编写底层驱动
驱动程序的时候应该比较好用，它可以绕开"&"和"|"进行位操作，而且更加节约内存空间。废话不多说
了，还是先来看看它的真面目吧：
bit-field来源:
bit-field是为了节约存储空间而创造的一种数� ......
哈哈！有幸在某网站发现这篇文章，读罢，觉得蛮有道理，发来大家一起共勉之
总是被同学们问到，如何学习C和C++才不茫然，才不是乱学，想了一下，这里给出一个总的回复。
' J$ |0 ?! p% w" t5 D6 D: c9 |0 B
一家之言，欢迎拍砖哈。
1、可以考虑先学习C.
/ U$ X+ X/ P; Y ......
指针,众所周知,时为一内存地址.抛开OS级别或更低的硬件级别不说,仅对应用内的使用进行小小的臆测讨论.
首先,在应用内,用malloc申请到的一块地址应该是连续的(猜测,逻辑上连续,实际上物理如何分布不予关注).
其次,数据存在在内存中都是以2进制形式存放.不存在数据类型,因此,对内存数据的操作,只要遵循进出类型一致即可.
� ......
