K& R练习1-18 [英] K&R exercise 1-18
问题描述
你好，
我一直在研究K& R书（目前只有第一章）的例子
和练习。经过大量的汗水和头发拉动，我想我有一个
解决方案，适用于第1页的前1-18页。
似乎工作但可能会丢失一些错误检查。你可以请
看看我的逻辑是否正确以及其他任何改进。
这不是作业，但它也可以。我想在C编程上获得一个
的处理能力，并且最终希望在接近退休时帮助GNU项目获得一些支持。
/ *函数从输入行中删除尾随空白和制表符* /
/ *而不打印任何空白行* /
#include< stdio.h>
#define最大1000 / *最大行长，包括''\'''标记* /
void remblank（char line []）;
int main（）
{
int c ，i;
i = 0;
char line [MAXIMUM];
c = getchar（）;
while （c！= EOF）
{
line [i] = c;
if（i ==（MAXIMUM - 1））/ *确保行是< = 1000 * /
line [i] =''\ n'';
if（line [i] =='' \ n''）
{
line [i + 1] =''\ 0'';
remblank（line） ;
i = 0;
}
其他
++ i;
c = getchar（）;
}
/ *打印最后一位，如果在最后一个换行符后有更多* /
/ * * /
if（c == EOF）
{
line [i] =''\ 0'';
while（line [i - 1] == （''\t''）|| line [i - 1] ==（''''））
{
line [i - 1] =''\ 0'';
--i;
}
printf（"％s"，line）;
}
返回0;
}
void remblank（char s []）
{
int i;
for（i = 0; s [i]！=''\ n''; i ++）/ *计算行中的字符* /
;
/ *如果换行前的字符是空格或制表符* /
/ *用换行符替换它并制作下一个* /
/ *字符数组标记的结尾* /
while（s [i - 1] ==（''\t''）|| s [i - 1] ==（''''））
{
s [i -1] =''\ n'';
s [i] =''\ 0'';
- i;
}
/ *如果是不是空白，打印行没有* /
/ *尾随空格或标签* /
if（s [0]！=''\ n''）
printf（"％s&q uot;，s）;
}
谢谢，
Eric
Eric ???é?????
你好，
我一直在研究K& R书（目前只有第一章）的例子和练习。经过大量的汗水和头发拉动之后，我认为我在第31页上有一个针对前1-18的解决方案。
它似乎有用，但可能会遗漏一些错误检查。你能否请你看看我的逻辑是否正确以及其他任何改进。
这不是一个功课，但它也可以。我正在努力获得关于C编程的处理能力，并且最终希望在我接近退休时帮助解决一些GNU项目。
/ *函数到从输入行* /
/ *剥去尾随空白和制表符而不打印任何空白行* /
#include< stdio.h>
#define MAXIMUM 1000 / *最大行长度，包括''\'''标记* /
void remblank（char line []）;
int main（）
{
int c，i;
i = 0;
char line [MAXIMUM];
c = getchar（）;
while（c！= EOF）
{line = [i] = c;
if（i ==（MAXIMUM - 1））/ *确保行是< = 1000 * /
行[i] =''\ n'';
if（line [i] ==''\ n''）
{
line [i + 1] ='' \\ 0'';
remblank（line）;
i = 0;
}
其他
++ i;
c = getchar（）;
}
/ *如果在最后一个换行符之后有更多* /
/ *，则打印最后一位* /
如果（c == EOF）
{
line [i] =''\ 0'';
while（line [i - 1] ==（''\t''）|| line [i - 1] ==（''''））
{
line [i - 1] =''\ 0'';
- i;
}
printf（"％s"，line）;
}
返回0;
}
void remblank（char s []）
{i / 0; s [i]！=''\ n''; i ++）/ *计算行中的字符* /
;
/ *如果换行前的字符是空格或制表符* /
/ *用换行符替换它并使下一个* /
/ *字符成为数组的结尾标记* /
while（s [i - 1] ==（''\t''）|| s [i - 1] ==（''''））
{
s [i -1] =''\ n'';
s [i] =''\ 0'';
- i;
}
/ *如果行不为空，则打印不带* /
的行/ *尾随空白或标签* /
if（s [0]！=''\ n''）
printf（"％s"，s）;
}
谢谢你，
Eric
#include< stdio.h>
#include< ; stdlib.h>
#define MAXQUEUE 1001
int advance（int指针）
{
if（指针< MAXQUEUE - 1）
返回指针+ 1;
其他
返回0;
}
int main（无效）
{
char blank [MAXQUEUE];
int head，tail;
int nonspace;
int retval;
int c;
int spaceJustPrinted; / * boolean：是打印的最后一个字符
空格？* /
retval = spaceJustPrinted = nonspace = head = tail = 0;
while（（c = getchar（））！= EOF）{
if（c ==''\ n''）{
head = tail = 0;
if（spaceJustPrinted == 1）/ *如果有一些尾随的空格是打印的...... * /
retval = EXIT_FAILURE;
if（nonspace）{
putchar（''\ n''）;
spaceJustPrinted = 0; / *这条指令不是真的
必要，因为
spaceJustPrinted仅用于
确定
返回值，但我们将保留此布尔值
如实* /
nonspace = 0; / *在条件内移动只是为了节省
不用
赋值* /
}
}
else if（c ==''''|| c ==''\t''）{
if（advance（head）== tail）{
putchar（空白[尾]）; / *这些空白字符被打印
提前
只是一个问题，如果它们落后，
我们会在我们点击时检查a \ n或EOF
* /
spaceJustPrinted = 1;
tail = advance（尾）;
nonspace = 1;
}
空白[head] = c;
head = advance（head）;
}
else {
while（head！= tail）{
putchar（blank [tail]）;
tail = advance（尾）;
}
putchar（c）;
spaceJustPrinted = 0;
nonspace = 1;
}
}
如果最后一行不是
/ *在EOF之前以换行符结束，
我们需要弄清楚这里是否打印了尾随空格* /
if（spaceJustPrinted == 1）/ * if一些尾随的空白是
打印... * /
retval = EXIT_FAILURE;
返回retval;
}
qi ********* @ yahoo.com.cn 写道：
< blockquote class =post_quotes>
Eric ???é?????
你好，
我一直在研究K& ; R书（目前仅有第一章）
实例和练习。经过大量的汗水和头发拉动之后，我认为我在第31页上有一个针对前1-18的解决方案。
它似乎有用，但可能会遗漏一些错误检查。你能否请你看看我的逻辑是否正确以及其他任何改进。
这不是一个功课，但它也可以。我正在尝试处理C编程，并最终希望在我接近退休时帮助解决一些GNU项目。
....程序切断以节省空间....
谢谢，
Eric
#include< stdio.h>
#include< stdlib.h>
#define MAXQUEUE 1001
int advance（int指针）
{
if（指针< MAXQUEUE - 1）
返回指针+ 1;
返回0;
}
int main（void）
{
char blank [MAXQUEUE];
int head，tail;
int nonspace;
int retval;
int c;
int spaceJustPrinted; / * boolean：是打印的最后一个字符
空格？* /
retval = spaceJustPrinted = nonspace = head = tail = 0;
while（（c = getchar（））！= EOF）{
if（c ==''\ n''）{
head = tail = 0;
if（spaceJustPrinted == 1）/ *如果打印了一些尾随的空白...... * /
retval = EXIT_FAILURE;
if（nonspace）{
putchar（''\ n''） ;
spaceJustPrinted = 0; / *这条指令实际上并不是必需的，因为
spaceJustPrinted仅用于确定
返回值，但我们会保持这个布尔值
真实* /
非空间= 0; / *在条件内移动只是为了保存一个不必要的
任务* /
}
}
如果（c ==''''|| c == ''\t''）{
if（advance（head）== tail）{
putchar（blank [tail]）; / *这些空白字符被打印
早期
只是一个问题，如果它们落后，
我们将检查当我们点击\\\
或EOF
* /
spaceJustPrinted = 1;
tail = advance（tail）;
nonspace = 1;
}
空白[head] = c;
head = advance（head）;
}
else {
while（head！= tail）{
putchar（空白[tail]）;
tail = advance （尾）;
}
putchar（c）;
spaceJustPrinted = 0;
nonspace = 1;
}
}
/ *如果最后一行在EOF之前没有用换行符结束，我们需要弄清楚是否在这里打印了尾随空格* /
if（spaceJustPrinted == 1 ）/ *如果打印了一些尾随的空格...... * /
retval = EXIT_FAILURE;
返回retval;
}
感谢您的回复。我需要一段时间才能完全消化这个并且
了解你的程序背后的逻辑。你的变量更多是描述性的，我需要记住这样做。我用
编译并测试了一个测试文件，我使用不同的行长度和尾随的标签和
空白。它给了我与我的版本相同的结果。我是b / b
在布尔逻辑语句（==，！=，||）中苦苦挣扎，因为我使用真值表并且布尔值非常好，因此
让我感到惊讶当天回来
代数。
谢谢，
Eric
删除" ;所有的垃圾邮件回复。
> Eric ???é?????
我一直在研究K& R书（目前只有第一章）的例子。和>练习。经过大量的汗水和头发拉动，我认为我有一个解决方案，请参阅第31页的前1-18。
< snip>
qi ********* @ yahoo.com.cn 写道：#include< stdio.h> ;
#include< stdlib.h>
#define MAXQUEUE 1001
< snip>
您可以告知OP可以从哪里获取代码。
看起来非常类似于......
http://users.powernet.co.uk/eton/kandr2/krx118 .html
-
彼得
Hello,
I have been working through the K&R book (only chapter one so far) examples
and exercises. After much sweat and hair pulling, I think I have a
solution for ex 1-18 on page 31.
It seems to work but may be missing some error checking. Can you please
take a look and see if my logic is correct and any other improvements.
This is not a homework but it could just as well be. I am trying to get a
handle on C programming and would eventually like to help out with some of
the GNU projects as I get closer to retirement.
/* function to strip trailing blanks and tabs from the input line */
/* and not to print any blank lines */
#include <stdio.h>
#define MAXIMUM 1000 /* maximum line length including ''\0'' marker */
void remblank(char line[]);
int main()
{
int c, i;
i = 0;
char line[MAXIMUM];
c = getchar();
while (c != EOF)
{
line[i] = c;
if (i == (MAXIMUM - 1)) /* make sure line is <= 1000 */
line[i] = ''\n'';
if (line[i] == ''\n'')
{
line[i + 1] = ''\0'';
remblank(line);
i = 0;
}
else
++i;
c = getchar();
}
/* print the last bit if there is more */
/* after the last newline */
if (c == EOF)
{
line[i] = ''\0'';
while (line[i - 1] == (''\t'') || line[i - 1] == ('' ''))
{
line[i - 1] = ''\0'';
--i;
}
printf("%s", line);
}
return 0;
}
void remblank(char s[])
{
int i;
for(i = 0; s[i] != ''\n''; i++) /* count characters in line */
;
/* if character before newline is a blank or tab */
/* replace it with a newline and make the next */
/* character an end of array marker */
while (s[i - 1] == (''\t'') || s[i - 1] == ('' ''))
{
s[i -1] = ''\n'';
s[i] = ''\0'';
--i;
}
/* if line is not blank, print the line without */
/* the trailing blanks or tabs */
if(s[0] != ''\n'')
printf("%s", s);
}
Thank you,
Eric
Eric ???é?????
Hello,
I have been working through the K&R book (only chapter one so far) examples
and exercises. After much sweat and hair pulling, I think I have a
solution for ex 1-18 on page 31.
It seems to work but may be missing some error checking. Can you please
take a look and see if my logic is correct and any other improvements.
This is not a homework but it could just as well be. I am trying to get a
handle on C programming and would eventually like to help out with some of
the GNU projects as I get closer to retirement.
/* function to strip trailing blanks and tabs from the input line */
/* and not to print any blank lines */
#include <stdio.h>
#define MAXIMUM 1000 /* maximum line length including ''\0'' marker */
void remblank(char line[]);
int main()
{
int c, i;
i = 0;
char line[MAXIMUM];
c = getchar();
while (c != EOF)
{
line[i] = c;
if (i == (MAXIMUM - 1)) /* make sure line is <= 1000 */
line[i] = ''\n'';
if (line[i] == ''\n'')
{
line[i + 1] = ''\0'';
remblank(line);
i = 0;
}
else
++i;
c = getchar();
}
/* print the last bit if there is more */
/* after the last newline */
if (c == EOF)
{
line[i] = ''\0'';
while (line[i - 1] == (''\t'') || line[i - 1] == ('' ''))
{
line[i - 1] = ''\0'';
--i;
}
printf("%s", line);
}
return 0;
}
void remblank(char s[])
{
int i;
for(i = 0; s[i] != ''\n''; i++) /* count characters in line */
;
/* if character before newline is a blank or tab */
/* replace it with a newline and make the next */
/* character an end of array marker */
while (s[i - 1] == (''\t'') || s[i - 1] == ('' ''))
{
s[i -1] = ''\n'';
s[i] = ''\0'';
--i;
}
/* if line is not blank, print the line without */
/* the trailing blanks or tabs */
if(s[0] != ''\n'')
printf("%s", s);
}
Thank you,
Eric
#include <stdio.h>
#include <stdlib.h>
#define MAXQUEUE 1001
int advance(int pointer)
{
if (pointer < MAXQUEUE - 1)
return pointer + 1;
else
return 0;
}
int main(void)
{
char blank[MAXQUEUE];
int head, tail;
int nonspace;
int retval;
int c;
int spaceJustPrinted; /*boolean: was the last character printed
whitespace?*/
retval = spaceJustPrinted = nonspace = head = tail = 0;
while ((c = getchar()) != EOF) {
if (c == ''\n'') {
head = tail = 0;
if (spaceJustPrinted == 1) /*if some trailing whitespace was
printed...*/
retval = EXIT_FAILURE;
if (nonspace) {
putchar(''\n'');
spaceJustPrinted = 0; /* this instruction isn''t really
necessary since
spaceJustPrinted is only used to
determine the
return value, but we''ll keep this boolean
truthful */
nonspace = 0; /* moved inside conditional just to save a
needless
assignment */
}
}
else if (c == '' '' || c == ''\t'') {
if (advance(head) == tail) {
putchar(blank[tail]); /* these whitespace chars being printed
early
are only a problem if they are trailing,
which we''ll check when we hit a \n or EOF
*/
spaceJustPrinted = 1;
tail = advance(tail);
nonspace = 1;
}
blank[head] = c;
head = advance(head);
}
else {
while (head != tail) {
putchar(blank[tail]);
tail = advance(tail);
}
putchar(c);
spaceJustPrinted = 0;
nonspace = 1;
}
}
/* if the last line wasn''t ended with a newline before the EOF,
we''ll need to figure out if trailing space was printed here */
if (spaceJustPrinted == 1) /*if some trailing whitespace was
printed...*/
retval = EXIT_FAILURE;
return retval;
}
qi*********@yahoo.com.cn wrote:
Eric ???é?????Hello,
I have been working through the K&R book (only chapter one so far)
examples
and exercises. After much sweat and hair pulling, I think I have a
solution for ex 1-18 on page 31.
It seems to work but may be missing some error checking. Can you please
take a look and see if my logic is correct and any other improvements.
This is not a homework but it could just as well be. I am trying to get
a handle on C programming and would eventually like to help out with some
of the GNU projects as I get closer to retirement.
....program cut off to save space ....
Thank you,
Eric
#include <stdio.h>
#include <stdlib.h>
#define MAXQUEUE 1001
int advance(int pointer)
{
if (pointer < MAXQUEUE - 1)
return pointer + 1;
else
return 0;
}
int main(void)
{
char blank[MAXQUEUE];
int head, tail;
int nonspace;
int retval;
int c;
int spaceJustPrinted; /*boolean: was the last character printed
whitespace?*/
retval = spaceJustPrinted = nonspace = head = tail = 0;
while ((c = getchar()) != EOF) {
if (c == ''\n'') {
head = tail = 0;
if (spaceJustPrinted == 1) /*if some trailing whitespace was
printed...*/
retval = EXIT_FAILURE;
if (nonspace) {
putchar(''\n'');
spaceJustPrinted = 0; /* this instruction isn''t really
necessary since
spaceJustPrinted is only used to
determine the
return value, but we''ll keep this boolean
truthful */
nonspace = 0; /* moved inside conditional just to save a
needless
assignment */
}
}
else if (c == '' '' || c == ''\t'') {
if (advance(head) == tail) {
putchar(blank[tail]); /* these whitespace chars being printed
early
are only a problem if they are trailing,
which we''ll check when we hit a \n or EOF
*/
spaceJustPrinted = 1;
tail = advance(tail);
nonspace = 1;
}
blank[head] = c;
head = advance(head);
}
else {
while (head != tail) {
putchar(blank[tail]);
tail = advance(tail);
}
putchar(c);
spaceJustPrinted = 0;
nonspace = 1;
}
}
/* if the last line wasn''t ended with a newline before the EOF,
we''ll need to figure out if trailing space was printed here */
if (spaceJustPrinted == 1) /*if some trailing whitespace was
printed...*/
retval = EXIT_FAILURE;
return retval;
}
Thank you for your reply. It will take me a while to fully digest this and
understand the logic behind your program. Your variables are much more
descriptive which I need to remember to do. I compiled and tested it with
a test file I made with different line lengths with trailing tabs and
blanks. It gave me the same results that I got with my version. I am
struggling through the boolean logic statements (==, !=, ||) which
surprised me as I use to be pretty good with truth tables and boolean
algebra back in the day.
Thanks,
Eric
Remove "all the spam" to reply.
> Eric ???é?????
I have been working through the K&R book (only chapter one so far) examples
and exercises. After much sweat and hair pulling, I think I have a
solution for ex 1-18 on page 31.<snip>
qi*********@yahoo.com.cn wrote: #include <stdio.h>
#include <stdlib.h>
#define MAXQUEUE 1001
<snip>
You could have informed the OP where the code could be sourced from.
It looks quite similar to that at...
http://users.powernet.co.uk/eton/kandr2/krx118.html
--
Peter
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