Can'；我无法理解C语言中的单词计数

[已解决] 我最近问了一个关于一些代码的问题，我认为我真的很理解这些代码

但几天后，当我回顾修订时，新的问题来自同一段代码（由Brian.W.Kernighnan（ISBN-13:978-8131704943）采用的C编程语言第二版）

代码如下：

#include <stdio.h>

#define IN  1
#define OUT 0

main()
{
    int nw, c, state;
    state = OUT;
    nw = 0;
    while ((c = getchar()) != EOF)
    {
        if (c == ' ' || c == '\n' || c == '\t')
            state = OUT;
        else if (state == OUT)
        {
            state = IN;
            ++nw;
        }
    }
    printf("%d", nw);
}

#包括
#在1中定义
#定义出0
main（）
{
北卡罗来纳州西北部；
状态=输出；
nw=0；
而（（c=getchar（））！=EOF）
{
如果（c=''| | c='\n'| | c='\t'）
状态=输出；
else if（state==OUT）
{
状态=IN；
++西北；
}
}
printf（“%d”，西北）；
}

所以我做了一些随机测试，发现了一些我无法解释或理解的东西：

为什么当我有

state=OUT

在

nw=0之后

当我正常运行这个代码时，它给出了正确的字数，但是当我交换

state=OUT和nw=0的顺序时，它总是返回等于0的答案，为什么会这样？？
我知道顺序在C语言中很重要，但为什么只有这个特定的顺序

2.if else stament的简要含义是什么

3.Acc。在这本书中，state变量被定义为定义getchar是否在一个单词中，但我不明白state变量究竟是如何做到的

4.作者如何使用等价和平等？？
我注意到当他在做一个条件时，他使用等价，否则使用相等，对吗

谢谢您……
以下是您发布的代码和一些评论：

#include <stdio.h>
#define IN  1 // in the code below, whenever you see IN, it's replaced by 1
#define OUT 0 // same as IN, but for 0

int main(void) {
  int nw, c, state; // nw is the number of the words
  // c stands for the character we get from input and state is the state that are
  // currently.

  // init state as OUT
  state = OUT;
  // init counter to 0
  nw = 0;

  // while user doesn't give EOF
  while ((c = getchar()) != EOF) {

    // we found whitespace, newline or tab
    if (c == ' ' || c == '\n' || c == '\t')
      state = OUT;                            // put state as OUT,
    // so that we do not count them as words
    else if (state == OUT) {                  // enter here only if state is OUT
      // Now, we see that we found a letter/number, which means that a word
      // was typed by the user.

      // set state as IN, so that we remember that we are eating the characters of
      // the word given (in the next loops)
      state = IN;

      // increase the counter of the words
      ++nw;
    }
  }

  // print the number of words received by the user
  printf("%d", nw);
  return 0;
}

当然，输出（正如您应该从上面的评论中猜到的）是：

2

让我们为input
sam
一步一步地运行（有趣的）代码：

// input: "sam" (without the quotes)

while ((c = getchar()) != EOF) { // eat first character, i.e. 's'

  /****** 1st execution of the loop ********************/

  // 's' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // first time we execute the loop so state is OUT,
  // thus we enter the loop
  else if (state == OUT) {

    // set state as IN
    state = IN;

    // increase the counter of the words
    ++nw;
  }

  /****************************************************/

  /****** 2nd execution of the loop ********************/
  // while loop's getchar() gives as 'a'

  // 'a' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // state is IN, so we don't go into this loop
  else if (state == OUT) {
    state = IN;
    ++nw;
  }

  /****************************************************/


  /****** 3rd execution of the loop ********************/
  // same as 2nd, but for 'm'

  /****************************************************/


  /****** 4rth execution of the loop ********************/
  // while loop's getchar() gives as '\n'

  // '\n' is going into this if (the c == '\n' is true
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;                // state sets to OUT

  // we are not going into this if else, since we already entered the above if!
  else if (state == OUT) {
    state = IN;
    ++nw;
  }

  /****************************************************/


  /****** 5th execution of the loop ********************/
  // while loop's getchar() gives as 'd' (first letter of dad)

  // 'd' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // state is OUT, so we go into this loop
  else if (state == OUT) {
    // set state as IN
    state = IN;

    // increase counter
    ++nw;
  }

  /****************************************************/

  // and so on :)
}

首先确保您理解这一点，然后回答您自己的问题。：）

此外，我们称之为代码，而不是脚本。不要急于进入脚本。
以下是您发布的代码和一些注释：

#include <stdio.h>
#define IN  1 // in the code below, whenever you see IN, it's replaced by 1
#define OUT 0 // same as IN, but for 0

int main(void) {
  int nw, c, state; // nw is the number of the words
  // c stands for the character we get from input and state is the state that are
  // currently.

  // init state as OUT
  state = OUT;
  // init counter to 0
  nw = 0;

  // while user doesn't give EOF
  while ((c = getchar()) != EOF) {

    // we found whitespace, newline or tab
    if (c == ' ' || c == '\n' || c == '\t')
      state = OUT;                            // put state as OUT,
    // so that we do not count them as words
    else if (state == OUT) {                  // enter here only if state is OUT
      // Now, we see that we found a letter/number, which means that a word
      // was typed by the user.

      // set state as IN, so that we remember that we are eating the characters of
      // the word given (in the next loops)
      state = IN;

      // increase the counter of the words
      ++nw;
    }
  }

  // print the number of words received by the user
  printf("%d", nw);
  return 0;
}

当然，输出（正如您应该从上面的评论中猜到的）是：

2

让我们为input
sam
一步一步地运行（有趣的）代码：

// input: "sam" (without the quotes)

while ((c = getchar()) != EOF) { // eat first character, i.e. 's'

  /****** 1st execution of the loop ********************/

  // 's' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // first time we execute the loop so state is OUT,
  // thus we enter the loop
  else if (state == OUT) {

    // set state as IN
    state = IN;

    // increase the counter of the words
    ++nw;
  }

  /****************************************************/

  /****** 2nd execution of the loop ********************/
  // while loop's getchar() gives as 'a'

  // 'a' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // state is IN, so we don't go into this loop
  else if (state == OUT) {
    state = IN;
    ++nw;
  }

  /****************************************************/


  /****** 3rd execution of the loop ********************/
  // same as 2nd, but for 'm'

  /****************************************************/


  /****** 4rth execution of the loop ********************/
  // while loop's getchar() gives as '\n'

  // '\n' is going into this if (the c == '\n' is true
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;                // state sets to OUT

  // we are not going into this if else, since we already entered the above if!
  else if (state == OUT) {
    state = IN;
    ++nw;
  }

  /****************************************************/


  /****** 5th execution of the loop ********************/
  // while loop's getchar() gives as 'd' (first letter of dad)

  // 'd' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // state is OUT, so we go into this loop
  else if (state == OUT) {
    // set state as IN
    state = IN;

    // increase counter
    ++nw;
  }

  /****************************************************/

  // and so on :)
}

首先确保您理解这一点，然后回答您自己的问题。：）

此外，我们称之为代码，而不是脚本。不要急于进入脚本。
以下是您发布的代码和一些注释：

#include <stdio.h>
#define IN  1 // in the code below, whenever you see IN, it's replaced by 1
#define OUT 0 // same as IN, but for 0

int main(void) {
  int nw, c, state; // nw is the number of the words
  // c stands for the character we get from input and state is the state that are
  // currently.

  // init state as OUT
  state = OUT;
  // init counter to 0
  nw = 0;

  // while user doesn't give EOF
  while ((c = getchar()) != EOF) {

    // we found whitespace, newline or tab
    if (c == ' ' || c == '\n' || c == '\t')
      state = OUT;                            // put state as OUT,
    // so that we do not count them as words
    else if (state == OUT) {                  // enter here only if state is OUT
      // Now, we see that we found a letter/number, which means that a word
      // was typed by the user.

      // set state as IN, so that we remember that we are eating the characters of
      // the word given (in the next loops)
      state = IN;

      // increase the counter of the words
      ++nw;
    }
  }

  // print the number of words received by the user
  printf("%d", nw);
  return 0;
}

当然，输出（正如您应该从上面的评论中猜到的）是：

2

让我们为input
sam
一步一步地运行（有趣的）代码：

// input: "sam" (without the quotes)

while ((c = getchar()) != EOF) { // eat first character, i.e. 's'

  /****** 1st execution of the loop ********************/

  // 's' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // first time we execute the loop so state is OUT,
  // thus we enter the loop
  else if (state == OUT) {

    // set state as IN
    state = IN;

    // increase the counter of the words
    ++nw;
  }

  /****************************************************/

  /****** 2nd execution of the loop ********************/
  // while loop's getchar() gives as 'a'

  // 'a' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // state is IN, so we don't go into this loop
  else if (state == OUT) {
    state = IN;
    ++nw;
  }

  /****************************************************/


  /****** 3rd execution of the loop ********************/
  // same as 2nd, but for 'm'

  /****************************************************/


  /****** 4rth execution of the loop ********************/
  // while loop's getchar() gives as '\n'

  // '\n' is going into this if (the c == '\n' is true
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;                // state sets to OUT

  // we are not going into this if else, since we already entered the above if!
  else if (state == OUT) {
    state = IN;
    ++nw;
  }

  /****************************************************/


  /****** 5th execution of the loop ********************/
  // while loop's getchar() gives as 'd' (first letter of dad)

  // 'd' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // state is OUT, so we go into this loop
  else if (state == OUT) {
    // set state as IN
    state = IN;

    // increase counter
    ++nw;
  }

  /****************************************************/

  // and so on :)
}

首先确保您理解这一点，然后回答您自己的问题。：）

此外，我们称之为代码，而不是脚本。不要急于进入脚本。
以下是您发布的代码和一些注释：

#include <stdio.h>
#define IN  1 // in the code below, whenever you see IN, it's replaced by 1
#define OUT 0 // same as IN, but for 0

int main(void) {
  int nw, c, state; // nw is the number of the words
  // c stands for the character we get from input and state is the state that are
  // currently.

  // init state as OUT
  state = OUT;
  // init counter to 0
  nw = 0;

  // while user doesn't give EOF
  while ((c = getchar()) != EOF) {

    // we found whitespace, newline or tab
    if (c == ' ' || c == '\n' || c == '\t')
      state = OUT;                            // put state as OUT,
    // so that we do not count them as words
    else if (state == OUT) {                  // enter here only if state is OUT
      // Now, we see that we found a letter/number, which means that a word
      // was typed by the user.

      // set state as IN, so that we remember that we are eating the characters of
      // the word given (in the next loops)
      state = IN;

      // increase the counter of the words
      ++nw;
    }
  }

  // print the number of words received by the user
  printf("%d", nw);
  return 0;
}

当然，输出（正如您应该从上面的评论中猜到的）是：

2

让我们为input
sam
一步一步地运行（有趣的）代码：

// input: "sam" (without the quotes)

while ((c = getchar()) != EOF) { // eat first character, i.e. 's'

  /****** 1st execution of the loop ********************/

  // 's' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // first time we execute the loop so state is OUT,
  // thus we enter the loop
  else if (state == OUT) {

    // set state as IN
    state = IN;

    // increase the counter of the words
    ++nw;
  }

  /****************************************************/

  /****** 2nd execution of the loop ********************/
  // while loop's getchar() gives as 'a'

  // 'a' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // state is IN, so we don't go into this loop
  else if (state == OUT) {
    state = IN;
    ++nw;
  }

  /****************************************************/


  /****** 3rd execution of the loop ********************/
  // same as 2nd, but for 'm'

  /****************************************************/


  /****** 4rth execution of the loop ********************/
  // while loop's getchar() gives as '\n'

  // '\n' is going into this if (the c == '\n' is true
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;                // state sets to OUT

  // we are not going into this if else, since we already entered the above if!
  else if (state == OUT) {
    state = IN;
    ++nw;
  }

  /****************************************************/


  /****** 5th execution of the loop ********************/
  // while loop's getchar() gives as 'd' (first letter of dad)

  // 'd' is not going into this if
  if (c == ' ' || c == '\n' || c == '\t')
    state = OUT;
  // state is OUT, so we go into this loop
  else if (state == OUT) {
    // set state as IN
    state = IN;

    // increase counter
    ++nw;
  }

  /****************************************************/

  // and so on :)
}

首先确保您理解这一点，然后回答您自己的问题。：）

此外，我们称之为代码，而不是脚本。不要急于进入脚本。
我认为您在这里复制的代码不正确。
状态==OUT
应该使用
=
而不是
==
，则
后面的代码>行。此问题似乎与主题无关，因为更正键入可以解决问题。很抱歉，键入错误，（已更正的脚本）但是我真的很想知道这个脚本，请不要把它从主题上划掉……不是答案，但是把一个C源文件称为脚本是相当混乱的……还有，你确定你的问题的第1部分在编辑后仍然有效吗？请不要因为OP的语言问题而抨击他。不是每个人都能说完美的英语。我认为你复制了代码此处错误。if（c==…
后面的
行的
状态==OUT；
应该使用
=
而不是
=
。此问题似乎与主题无关，因为更正错误可以解决问题。抱歉，键入错误，（更正的脚本）但是我真的很想知道这个脚本，请不要把它从主题上划掉……不是答案，但是把一个C源文件称为脚本是相当混乱的……还有，你确定你的问题的第1部分在编辑后仍然有效吗？请不要因为OP的语言问题而抨击他。不是每个人都能说完美的英语。我认为你复制了代码此处错误。if（c==…
后面的
行的
状态==OUT；
应该使用
=
而不是
=
。此问题似乎与主题无关，因为更正错误可以解决问题。抱歉，键入错误，（更正的脚本）但是我真的很想知道这个脚本，请不要把它从主题上划掉……不是答案，但是把一个C源文件称为脚本是相当混乱的……还有，你确定你的问题的第1部分在编辑后仍然有效吗？请不要因为OP的语言问题而抨击他。不是每个人都能说完美的英语。我认为你复制了代码此处错误。if（c==…
后面的
行的
状态==OUT；
应该使用
=
而不是
=
。此问题似乎与主题无关，因为更正错误可以解决问题。抱歉，键入错误，（更正的脚本）但是我真的很想知道这个脚本，请不要把它从主题上划掉……不是答案，但是把一个C源文件称为脚本是相当令人困惑的……还有，你确定你的问题的第一部分在编辑后仍然有效吗？请不要因为他的语言问题抨击OP。不是每个人都能说一口流利的英语。谢谢，但是你能打电话给我吗l告诉我state=in如何吃掉字符？？我也很抱歉造成混乱……@ArchKudo不客气。对我来说，没有问题。：
getchar（）
是吃掉字符的人。When
state