从文件中读取数字 [英] Reading numbers from a file
问题描述
我正在从一个文件中读取一串数字（使用Borland C ++ Builder
6），我这样做是这样的：首先我使用FileRead将文件中的所有
数据存储到char *变量（适当地称为''data''）。
然后，我读取每个数字使用
char * ptr;
int value;
[...]
ptr =& data [position];
sscanf（ptr，"％i"，& value）;
position + = IntToStr（value）.Length（）;
numbers [i] = value;
（当然，所有这些都在循环中）。
这个方法似乎工作正常，但是Borland CodeGuard告诉我
每个sscanf调用都有一个访问超限，所以我猜有一个
更好的方式。你能帮帮我吗？
非常感谢，
LuTHieR
Hi,
I''m reading a string of numbers from a file (using Borland C++ Builder
6), and I''m doing it like this: first I use FileRead to store all the
data in the file to a char* variable (appropriately called ''data'').
Then, I read every number using
char *ptr;
int value;
[...]
ptr = &data[position];
sscanf (ptr, "%i", &value);
position += IntToStr(value).Length();
numbers[i] = value;
(All of it inside of a loop, of course).
This method seems to be working OK, but Borland CodeGuard tells me that
there''s an access overrun in each sscanf call, so I guess there is a
better way of doing it. Could you please help me?
Big thanks,
LuTHieR
推荐答案
LuTHieR写道：
LuTHieR wrote:
我正在从一个文件中读取一串数字（使用Borland C ++ Builder
6），我就是我这样做：首先我使用FileRead将文件中的所有数据存储到char *变量（适当地称为''data''）。
然后，我使用
char * ptr;
int value;
[...]
ptr =& data [position];
sscanf（ptr，"％i"& value）;
position + = IntToStr（value）.Length（）;
numbers [i] = value;
（当然所有这些都在循环中）。
这种方法似乎工作正常，但是Borland CodeGuard告诉我，每次sscanf调用都有访问溢出，所以我猜测有更好的方法。你能帮帮我吗？
非常感谢，
LuTHieR
Hi,
I''m reading a string of numbers from a file (using Borland C++ Builder
6), and I''m doing it like this: first I use FileRead to store all the
data in the file to a char* variable (appropriately called ''data'').
Then, I read every number using
char *ptr;
int value;
[...]
ptr = &data[position];
sscanf (ptr, "%i", &value);
position += IntToStr(value).Length();
numbers[i] = value;
(All of it inside of a loop, of course).
This method seems to be working OK, but Borland CodeGuard tells me that
there''s an access overrun in each sscanf call, so I guess there is a
better way of doing it. Could you please help me?
Big thanks,
LuTHieR
在C ++中你应该尽量避免使用CI / O函数除非你有充足的理由使用它们。 sscanf及其变种众所周知
易于使用不正确。这是一个如何使用
C ++的字符串流来做同样的例子。修改你的需求：
#include< iostream>
#include< sstream>
int main（）
{
char data [] =" 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47" ;
std :: istringstream ss（数据）;
int i;
while（ss>> i）
std :: cout<< i<< std :: endl;
}
-
Alan Johnson
In C++ you should try avoid using the C I/O functions unless you have a
good reason to be using them. sscanf and its variants are notoriously
easy to use incorrectly. Here is an example of how to do the same using
C++''s stringstreams. Modify to your needs:
#include <iostream>
#include <sstream>
int main()
{
char data[] = "2 3 5 7 11 13 17 19 23 29 31 37 41 43 47" ;
std::istringstream ss(data) ;
int i ;
while (ss >> i)
std::cout << i << std::endl ;
}
--
Alan Johnson
谢谢:)
还有一个问题......如果数据在实际数据之前包含一个字符串
（类似data [] =" label 1 2 3 4 5 6 7 8），我怎么能轻松地读取它？b / b
再次感谢
LuTHieR
Alan Johnson ha escrito：
Thanks :)
One more question...if data contains a String before the actual data
(something like data[] = "label 1 2 3 4 5 6 7 8"), how can I easily
read it?
Thanks again
LuTHieR
Alan Johnson ha escrito:
LuTHieR写道：
LuTHieR wrote:
我正在读一串文件中的数字（使用Borland C ++ Builder
6），我这样做：首先我使用FileRead将文件中的所有数据存储到char *变量中（适当地称为''数据''）。
然后，我使用
char * ptr读取每个数字;
int value;
[...]
ptr =& data [position];
sscanf（ptr，"％i"，& value）;
position + = IntToStr（value）.Length（ ）;
数字[i] =价值;
（当然所有这些都在一个循环中。
这个方法似乎工作正常，但是Borland CodeGuard告诉我，每个sscanf调用都有一个访问超限，所以我想那里是一种更好的方法。你能帮帮我吗？
非常感谢，
LuTHieR
Hi,
I''m reading a string of numbers from a file (using Borland C++ Builder
6), and I''m doing it like this: first I use FileRead to store all the
data in the file to a char* variable (appropriately called ''data'').
Then, I read every number using
char *ptr;
int value;
[...]
ptr = &data[position];
sscanf (ptr, "%i", &value);
position += IntToStr(value).Length();
numbers[i] = value;
(All of it inside of a loop, of course).
This method seems to be working OK, but Borland CodeGuard tells me that
there''s an access overrun in each sscanf call, so I guess there is a
better way of doing it. Could you please help me?
Big thanks,
LuTHieR
在C ++中你应该尽量避免使用CI / O函数，除非你有一个
使用它们的充分理由。众所周知，sscanf及其变种很容易错误地使用。这是一个如何使用C ++的stringstreams做同样的例子。修改你的需求：
#include< iostream>
#include< sstream>
int main（）
{
char data [] =" 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 ;
std :: istringstream ss（data）;
int i;
while（ss>> i）
std :: cout<< i<< std :: endl;
}
-
Alan Johnson
In C++ you should try avoid using the C I/O functions unless you have a
good reason to be using them. sscanf and its variants are notoriously
easy to use incorrectly. Here is an example of how to do the same using
C++''s stringstreams. Modify to your needs:
#include <iostream>
#include <sstream>
int main()
{
char data[] = "2 3 5 7 11 13 17 19 23 29 31 37 41 43 47" ;
std::istringstream ss(data) ;
int i ;
while (ss >> i)
std::cout << i << std::endl ;
}
--
Alan Johnson
Don 打扰回答，就像使用>>一样简单操作符为
字符串类型。
再次感谢
LuTHieR
LuTHieR ha escrito：
Don''t bother answering, it was as simple as using the >> operator to a
string type.
Thanks again
LuTHieR
LuTHieR ha escrito:
谢谢:)
还有一个问题......如果数据在实际数据之前包含一个字符串
（类似data [] ="标签1 2 3 4 5 6 7 8），我怎样才能轻松阅读？
再次感谢
LuTHieR
Alan Johnson ha escrito ：
Thanks :)
One more question...if data contains a String before the actual data
(something like data[] = "label 1 2 3 4 5 6 7 8"), how can I easily
read it?
Thanks again
LuTHieR
Alan Johnson ha escrito:
LuTHieR写道：
LuTHieR wrote:
我正在从文件中读取一串数字（使用Borland C ++ Builder
6），我这样做：首先我使用FileRead将文件中的所有数据存储到char *变量（适当地称为''data''）。
然后，我读了每个数字使用
char * ptr;
int value;
[...]
ptr =& data [position];
sscanf（ptr，"％i"，& value）;
position + = IntToStr（value）.Length（）;
number s [i] = value;
（当然所有这些都在循环中）。
这种方法似乎工作正常，但Borland CodeGuard告诉我
每个sscanf调用都有一个访问超限，所以我猜有更好的方法。你能帮帮我吗？
非常感谢，
LuTHieR
Hi,
I''m reading a string of numbers from a file (using Borland C++ Builder
6), and I''m doing it like this: first I use FileRead to store all the
data in the file to a char* variable (appropriately called ''data'').
Then, I read every number using
char *ptr;
int value;
[...]
ptr = &data[position];
sscanf (ptr, "%i", &value);
position += IntToStr(value).Length();
numbers[i] = value;
(All of it inside of a loop, of course).
This method seems to be working OK, but Borland CodeGuard tells me that
there''s an access overrun in each sscanf call, so I guess there is a
better way of doing it. Could you please help me?
Big thanks,
LuTHieR
在C ++中你应该尽量避免使用CI / O函数，除非你有一个
使用它们的充分理由。众所周知，sscanf及其变种很容易错误地使用。这是一个如何使用C ++的stringstreams做同样的例子。修改你的需求：
#include< iostream>
#include< sstream>
int main（）
{
char data [] =" 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 ;
std :: istringstream ss（data）;
int i;
while（ss>> i）
std :: cout<< i<< std :: endl;
}
-
Alan Johnson
In C++ you should try avoid using the C I/O functions unless you have a
good reason to be using them. sscanf and its variants are notoriously
easy to use incorrectly. Here is an example of how to do the same using
C++''s stringstreams. Modify to your needs:
#include <iostream>
#include <sstream>
int main()
{
char data[] = "2 3 5 7 11 13 17 19 23 29 31 37 41 43 47" ;
std::istringstream ss(data) ;
int i ;
while (ss >> i)
std::cout << i << std::endl ;
}
--
Alan Johnson
这篇关于从文件中读取数字的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
