挣扎着弦乐 [英] struggling with strings
问题描述
大家好！
我正在尝试学习C编程，但我的java背景会阻止我的
大脑。
我有一本书很多功能，其中一些不能正常工作，所以我有机会通过校正在C中锻炼
（奇怪，是吧？）。 />
例如，我想编写一个函数，从字符串中删除给定子串的所有出现的
。
到目前为止我有两个函数：
1.从字符串中删除第一个子字符串（我在这本可怕的书中对函数进行了
更正之后做了一遍：
char * strstr_rem_first（char * string，char * substring）{
int i，j，k，loc = -1;
for（i = 0; string [i]&&（loc == - 1）; i ++）{
for（j = i，k = 0; string [j] == substring [k]; j ++，k ++）
if（！substring [k + 1]）
loc = i;
if （loc！= -1）{//找到子串
for（k = 0; substring [k]; k ++）; {
for（j = loc，i = loc + k;串[I]; j ++，i ++）{
string [j] = string [i];
string [i] =''\''';
}
}
}
}
返回（字符串）;
}
2.找到子串的最右边索引（如果找不到则返回-1）：
int substring_index（const char * string，const char * substring）{
int i，j，k;
for（i = 0; string [i]; i ++）
for（j = i，k = 0; string [j] == substring [k]; j ++，k ++）
if（！substring [k + 1]）
返回（i）;
返回（-1）;
}
现在，武装这些我想构建删除所有
子串的函数。
我虽然有类似这样的事情：
while（substring_index（）> 0）
string_original变为substring_rem_first
返回string_original
不幸的是，因为字符串被视为数组，我不能将
转移引用作为e我已经习惯了，我无法弄清楚如何在C中完成它。
我拖着一些指针和一些strcpy（）等徒劳无功。
特别是这个''string_original变成substring_rem_first''困扰
我。
我总是以''undefined''引用''结束'' substring_rem_first''。
你能救我吗？ :-)
Hi guys!
I am trying to learn C programming but my java background blocks my
brains.
I have a book with a lot of functions and some of them don''t work
correctly, so I have opportunity to exercise in C by correction
(strange, huh?).
For example, i want to write function that removes all occurences of
given substring from string.
I have two functions so far:
1. removes first substring from the string (i made it after
corrections of the function that i had in the horrible book:
char *strstr_rem_first(char *string, char *substring) {
int i, j, k, loc=-1;
for(i=0; string[i] && (loc==-1); i++) {
for(j=i, k=0; string[j] ==substring[k];j++, k++)
if(!substring[k+1])
loc=i;
if(loc != -1) { //substring was found
for(k=0; substring[k];k++); {
for(j=loc, i=loc+k; string[i]; j++, i++) {
string[j] = string[i];
string[i]=''\0'';
}
}
}
}
return (string);
}
2. finds rightmost index of the substring (returns -1 if not found):
int substring_index(const char *string, const char *substring) {
int i, j, k;
for(i=0; string[i];i++)
for(j=i,k=0; string[j] == substring[k]; j++, k++)
if(!substring[k+1])
return(i);
return(-1);
}
Now, armed with these I wanted to construct function that removes all
substrings.
I though about somthing like this:
while(substring_index() > 0)
string_original becomes substring_rem_first
return string_original
Unfortunately, because strings are treated as arrays and i can''t
transfer references as easily as i got used to, i can''t figure out how
to accomplish it in C.
I shuffled some pointers and some strcpy() etc in vain.
Especially this ''string_original becomes substring_rem_first'' bothers
me.
I always end up with ''undefined'' reference to ''substring_rem_first''.
Could you help me out? :-)
推荐答案
你好tuchka，
" tuchka" < IA *** @ hotmail.com> schrieb im Newsbeitrag
新闻：5f ************************** @ posting.google.c om ...
Hi tuchka,
"tuchka" <ia***@hotmail.com> schrieb im Newsbeitrag
news:5f**************************@posting.google.c om...
1.从字符串中删除第一个子字符串（我在可怕的书中对函数进行了更正后进行了修改：
2.查找子字符串的最右边索引（如果没有找到则返回-1）：
1. removes first substring from the string (i made it after
corrections of the function that i had in the horrible book:
2. finds rightmost index of the substring (returns -1 if not found):
查看在string.h中声明的函数。:-)
这里是删除所有substring的函数。来自string：
#include< string.h>
char * strstr_rem_all（char * string，const char * substring ）{
char *发生; int substr_len = strlen（substring）; int move_len =
strlen（string） - substr_len + 1; / * +1 b / c终止''\ 0''* /
while（occurrence = strstr（字符串，子串））{
memmove（发生， string + substr_len，move_len）;
}
返回字符串;
}
memmove（ ）用来代替memcpy（），因为它处理重叠的
副本。 :-)
我希望有所帮助！ :-)
问候，
Ekkehard Morgenstern。
Check out the functions declared in "string.h". :-)
Here''s a function to remove all occurrences of "substring" from "string":
#include <string.h>
char* strstr_rem_all( char* string, const char* substring ) {
char* occurrence; int substr_len = strlen( substring ); int move_len =
strlen( string ) - substr_len + 1; /* +1 b/c of terminating ''\0'' */
while ( occurrence = strstr( string, substring ) ) {
memmove( occurrence, string + substr_len, move_len );
}
return string;
}
memmove() is used instead of memcpy(), because it handles overlapping
copies. :-)
I hope that helps! :-)
Regards,
Ekkehard Morgenstern.
谢谢你，Ekkehard，
我看到这个功能怎么可能有效但我仍然无法得到
工作。
你写的函数给出了以下内容错误：
C：\ Sveta \ C_PROG~1 \ STRING~1> str_test
123fart456fart789fart
反向traf987traf654traf321是traf987traf654traf321
与X填充成为xxxxxxxxxxxxxxxxxxxxx
除去第一屁后成为123456fart789fart
移除所有屁成了
后
123art456rt456rt456rt456rt456rt456rt456rt？
在EIP = 0000772e
EAX = 00000000 EBX退出由于信号SIGSEGV
一般保护性错误= 00000000 ECX = FFFFFFFF EDX = FFFFFFFF ESI = FFFFFFFF
EDI = FFFFFFFF
EBP = 00090390 ESP = 0008ef6c
方案= C：\ SVETA \ C_PROG~1 \STRING~1 \STR_TEST.EXE
cs：sel = 01a7 base = 029a0000 limit = 0009ffff
ds：sel = 01af base = 029a0000 limit = 0009ffff
es：sel = 01af base = 029a0000极限= 0009ffff
FS：SEL =拉丁文扩展-A基= 00005a50极限= 0000FFFF
GS：SEL = 01BF碱= 00000000极限= 0010ffff
ss：sel = 01af base = 029a0000 limit = 0009ffff
app stack：[00090560..00010560] Exceptn stack：[000104c0..0000e580]
电话帧追溯EIP：
0x0000772e
0x00003946
0x00001b82
0x000033d8
我像这样重写它但是我已经''未定义引用''
str_rem_first（string，substring）：
char * strstr_rem_all（char * string，const char * substring）{
// char occurence [strlen（string）];
char * ptr;
int substr_len = strlen（substring）;
int move_len = strlen（string）-substr_len + 1;
while（ptr = strstr（string） ，substring））{
char occurence [strlen（string）];
memmove（occurence，str_rem_first（string，substring），
strlen（string）-substr_len + 1）;
}
返回字符串;
}
叹息，感叹:-(
为什么郎。真是太难了？
Ekkehard Morgenstern < EK ****************** @ onlinehome.de>在留言新闻中写道：< bp ********** @ online.de> ...
Thank you, Ekkehard,
I see how that function could''ve work but i still cannot get it to
work.
The function as written by you gives the following error:
C:\Sveta\C_PROG~1\STRING~1>str_test
123fart456fart789fart
Reverse traf987traf654traf321 is traf987traf654traf321
Filled with x became xxxxxxxxxxxxxxxxxxxxx
After removing first fart became 123456fart789fart
After removing all fart became
123art456rt456rt456rt456rt456rt456rt456rt?
Exiting due to signal SIGSEGV
General Protection Fault at eip=0000772e
eax=00000000 ebx=00000000 ecx=ffffffff edx=ffffffff esi=ffffffff
edi=ffffffff
ebp=00090390 esp=0008ef6c
program=C:\SVETA\C_PROG~1\STRING~1\STR_TEST.EXE
cs: sel=01a7 base=029a0000 limit=0009ffff
ds: sel=01af base=029a0000 limit=0009ffff
es: sel=01af base=029a0000 limit=0009ffff
fs: sel=017f base=00005a50 limit=0000ffff
gs: sel=01bf base=00000000 limit=0010ffff
ss: sel=01af base=029a0000 limit=0009ffff
App stack: [00090560..00010560] Exceptn stack: [000104c0..0000e580]
Call frame traceback EIPs:
0x0000772e
0x00003946
0x00001b82
0x000033d8
I re-wrote it like this but again i''ve got ''undefined reference'' for
str_rem_first(string,substring):
char *strstr_rem_all(char *string, const char *substring) {
//char occurence[strlen(string)];
char *ptr;
int substr_len=strlen(substring);
int move_len=strlen(string)-substr_len+1;
while(ptr=strstr(string, substring)) {
char occurence[strlen(string)];
memmove(occurence, str_rem_first(string,substring),
strlen(string)-substr_len+1);
}
return string;
}
Sigh, sigh :-(
Why the lang. is so hard?
"Ekkehard Morgenstern" <ek******************@onlinehome.de> wrote in message news:<bp**********@online.de>...
嗨tuchka，
tuchka < IA *** @ hotmail.com> schrieb im Newsbeitrag
新闻：5f ************************** @ posting.google.c om ...
Hi tuchka,
"tuchka" <ia***@hotmail.com> schrieb im Newsbeitrag
news:5f**************************@posting.google.c om...
1.从字符串中删除第一个子字符串（我在可怕的书中对函数进行了更正后进行了修改：
2.找到子字符串的最右边索引（如果是，则返回-1）未找到）：
1. removes first substring from the string (i made it after
corrections of the function that i had in the horrible book:
2. finds rightmost index of the substring (returns -1 if not found):
查看在string.h中声明的函数。:-)
这是一个删除所有出现的函数的函数"子"来自string：
#include< string.h>
char * strstr_rem_all（char * string，const char * substring）{
char *发生; int substr_len = strlen（substring）; int move_len =
strlen（string） - substr_len + 1; / * +1 b / c终止''\ 0''* /
while（occurrence = strstr（字符串，子串））{
memmove（occurrence，字符串+ substr_len，move_len）;
}
返回字符串;
使用memmove（）代替memcpy（），因为它处理重叠的
副本。 :-)
我希望有所帮助！ :-)
问候，
Ekkehard Morgenstern。
Check out the functions declared in "string.h". :-)
Here''s a function to remove all occurrences of "substring" from "string":
#include <string.h>
char* strstr_rem_all( char* string, const char* substring ) {
char* occurrence; int substr_len = strlen( substring ); int move_len =
strlen( string ) - substr_len + 1; /* +1 b/c of terminating ''\0'' */
while ( occurrence = strstr( string, substring ) ) {
memmove( occurrence, string + substr_len, move_len );
}
return string;
}
memmove() is used instead of memcpy(), because it handles overlapping
copies. :-)
I hope that helps! :-)
Regards,
Ekkehard Morgenstern.
" Ekkehard Morgenstern" < EK ****************** @ onlinehome.de>在留言新闻中写道：< bp ********** @ online.de> ...
"Ekkehard Morgenstern" <ek******************@onlinehome.de> wrote in message news:<bp**********@online.de>...
嗨tuchka，
tuchka < IA *** @ hotmail.com> schrieb im Newsbeitrag
新闻：5f ************************** @ posting.google.c om ...
Hi tuchka,
"tuchka" <ia***@hotmail.com> schrieb im Newsbeitrag
news:5f**************************@posting.google.c om...
1.从字符串中删除第一个子字符串（我在可怕的书中对函数进行了更正后进行了修改：
2.找到子字符串的最右边索引（如果是，则返回-1）未找到）：
检查在string.h中声明的函数。:-)
这是一个删除所有substring的函数。来自string：
#include< string.h>
char * strstr_rem_all（char * string，const char * substring）{
char *发生; int substr_len = strlen（substring）; int move_len =
strlen（string） - substr_len + 1; / * +1 b / c终止''\ 0''* /
while（occurrence = strstr（字符串，子串））{
memmove（occurrence，字符串+ substr_len，move_len）;
}
返回字符串;
使用memmove（）代替memcpy（），因为它处理重叠的
副本。 ： - ）
1. removes first substring from the string (i made it after
corrections of the function that i had in the horrible book:
2. finds rightmost index of the substring (returns -1 if not found):
Check out the functions declared in "string.h". :-)
Here''s a function to remove all occurrences of "substring" from "string":
#include <string.h>
char* strstr_rem_all( char* string, const char* substring ) {
char* occurrence; int substr_len = strlen( substring ); int move_len =
strlen( string ) - substr_len + 1; /* +1 b/c of terminating ''\0'' */
while ( occurrence = strstr( string, substring ) ) {
memmove( occurrence, string + substr_len, move_len );
}
return string;
}
memmove() is used instead of memcpy(), because it handles overlapping
copies. :-)
这里有点奇怪。
小心你要动多少......最初的长度
字符串 - 子串+1的长度。这不会在
循环内部发生变化，但每次字符串变短时都会发生变化。
这个怎么样？它应该工作。
char * strstr_rem_all（char * string，const char * substring）{
char * occurrence;
int substr_len = strlen（substring）;
int move_len;
while（occurrence = strstr（string，substring））{
move_len = strlen （发生） - substr_len + 1;
memmove（发生，发生+ substr_len，move_len）;
}
返回字符串;
}
我希望有所帮助！ :-)
问候，
Ekkehard Morgenstern。
Isn''t there something a bit weird here.
Be careful abt how much you are moving ... the length of the initial
string - that of the substring +1 . This does not change inside the
loop but each time the string gets shorter.
What about this ? It should work.
char* strstr_rem_all( char* string, const char* substring ) {
char* occurrence;
int substr_len = strlen( substring );
int move_len;
while ( occurrence = strstr( string, substring ) ) {
move_len = strlen( occurrence ) - substr_len + 1;
memmove( occurrence, occurrence + substr_len, move_len );
}
return string;
}
I hope that helps! :-)
Regards,
Ekkehard Morgenstern.
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