strcpy - 我的实现 [英] strcpy - my implementation
问题描述
我已经创建了自己的strcpy库函数实现。我想
喜欢改进评论：
/ *我的版本strcpy - 一个C库函数* /
#include< stdio.h>
#include< stdlib.h>
#include< unistd.h>
#include< string.h>
enum {ARRSIZE = 101};
char * my_strcpy（char *，char *）;
int main（int argc，char ** argv）
{
char * pc;
char arr_in [ARRSIZE];
char arr_out [ARRSIZE];
memset（arr_in，''\'''， ARRSIZE）;
memset（arr_out，''\''，ARRSIZE）;
if（2！= argc）
{
perror（USAGE：./ exec \你的输入\" \ n"）;
退出（EXIT_FAILURE）;
}
其他
{
strcpy（arr_in，argv [1]）;
}
pc = my_strcpy（arr_out，arr_in）;
while（* pc ）
{
printf（" * pc =％c \ nn"，* pc ++）;
}
返回EXIT_SUCCESS;
}
char * my_strcpy（char * arr_out，char * arr_in）
{
char * pc;
pc = arr_out;
while（（* arr_out ++ = * arr_in ++ ））;
返回电脑;
}
===============输出======================
[arnuld @ dune ztest] $ gcc -ansi -pedantic -Wall - Wextra check_STRCPY.c
[arnuld @ dune ztest] $ ./a.out赞
* pc = l
* pc = i
* pc = k
* pc = e
[arnuld @ dune ztest] $
它工作正常没有麻烦。现在，如果您更改
my_strcpy中的最后一次回复来自return pc返回return arr_out，然后在
main（）中循环时根本不打印任何东西。我真的不理解它。
使用thr数组名称会给出一个指向它的第一个元素的指针但是int htis
它给出一个指向它最后一个元素的指针。为什么？这就是我为什么
引入额外的char * pc的原因。首先。
-
www.lispmachine.wordpress.com
我的电子邮件是@上面的博客。
谷歌群组被阻止。原因：过度垃圾邮件
I have created my own implementation of strcpy library function. I would
like to have comments for improvements:
/* My version of "strcpy - a C Library Function */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
enum { ARRSIZE = 101 };
char* my_strcpy( char*, char* );
int main( int argc, char** argv )
{
char* pc;
char arr_in[ARRSIZE];
char arr_out[ARRSIZE];
memset( arr_in, ''\0'', ARRSIZE );
memset( arr_out, ''\0'', ARRSIZE );
if( 2 != argc )
{
perror("USAGE: ./exec \" your input \"\n");
exit( EXIT_FAILURE );
}
else
{
strcpy( arr_in , argv[1] );
}
pc = my_strcpy( arr_out, arr_in );
while( *pc )
{
printf("*pc = %c\n", *pc++);
}
return EXIT_SUCCESS;
}
char* my_strcpy( char* arr_out, char* arr_in )
{
char* pc;
pc = arr_out;
while( (*arr_out++ = *arr_in++) ) ;
return pc;
}
=============== OUTPUT ======================
[arnuld@dune ztest]$ gcc -ansi -pedantic -Wall -Wextra check_STRCPY.c
[arnuld@dune ztest]$ ./a.out like
*pc = l
*pc = i
*pc = k
*pc = e
[arnuld@dune ztest]$
It works fine without troubles. Now if you change the last return call in
my_strcpy from "return pc" to return "return arr_out", then while loop in
main() will not print anything at all. I really did not understand it.
Using thr array name will give a pointer to its 1st element but int htis
case it is giving a pointer to its last element. Why ? Thats why I
introduced the extra "char* pc" in first place.
--
www.lispmachine.wordpress.com
my email is @ the above blog.
Google Groups is Blocked. Reason: Excessive Spamming
推荐答案
gcc -ansi -pedantic -Wall -Wextra check_STRCPY.c
[ arnuld @ dune ztest]
gcc -ansi -pedantic -Wall -Wextra check_STRCPY.c
[arnuld@dune ztest]
./ a.out like
* pc = l
* pc = i
* pc = k
* pc = e
[arnuld @ dune ztest]
./a.out like
*pc = l
*pc = i
*pc = k
*pc = e
[arnuld@dune ztest]
它运行正常没有麻烦。现在，如果您更改
my_strcpy中的最后一次回复来自return pc返回return arr_out，然后在
main（）中循环时根本不打印任何东西。我真的不理解它。
使用thr数组名称会给出一个指向它的第一个元素的指针但是int htis
它给出一个指向它最后一个元素的指针。为什么？这就是我为什么
引入额外的char * pc的原因。首先。
-
www.lispmachine.wordpress.com
我的电子邮件是@上面的博客。
谷歌群组被阻止。原因：过度垃圾邮件
It works fine without troubles. Now if you change the last return call in
my_strcpy from "return pc" to return "return arr_out", then while loop in
main() will not print anything at all. I really did not understand it.
Using thr array name will give a pointer to its 1st element but int htis
case it is giving a pointer to its last element. Why ? Thats why I
introduced the extra "char* pc" in first place.
--
www.lispmachine.wordpress.com
my email is @ the above blog.
Google Groups is Blocked. Reason: Excessive Spamming
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