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Reading file path from user in simple format “c:filessample.txt”

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0

I am trying to read file path from user as command line in simple format
ex:

path="c:filessample.txt"

but when trying to access using file.open("c:filessample.txt");
file not found.

so i used path.replace(path.begin(),path.end(),"\","\\") for it to change to \ but its not working.

Help me!!

c++ string

share|improve this question

edited Mar 8 at 5:48

Ansi

19138

asked Mar 8 at 5:42

lalit Kohlilalit Kohli

11

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  A single '' in a string is an escape character, but not a "" , the real string of the path is "c:(f)iles(s)ample.txt", so the replace function will not find the "".
  
  – Drake Wu - MSFT
  Mar 8 at 6:07
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Instead of path.replace, why not initialize path as C:\files\sample.txt ?
  
  – Sailesh D
  Mar 8 at 6:08
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  end user is not aware about computer field they can just copy the file path and paste so it could create problems further.
  
  – lalit Kohli
  Mar 8 at 6:18
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You don't need to double up on backslashes in runtime data, only in compile-time literals.
  
  – Remy Lebeau
  Mar 8 at 6:20
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  To be not confused with char escaping use the special form of defining string liberals that disables char escaping: file.open(R"(c:filessample.txt)");
  
  – S.M.
  Mar 8 at 6:37
  

  
  
  
  

add a comment | 

0

I am trying to read file path from user as command line in simple format
ex:

path="c:filessample.txt"

but when trying to access using file.open("c:filessample.txt");
file not found.

so i used path.replace(path.begin(),path.end(),"\","\\") for it to change to \ but its not working.

Help me!!

c++ string

share|improve this question

edited Mar 8 at 5:48

Ansi

19138

asked Mar 8 at 5:42

lalit Kohlilalit Kohli

11

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  A single '' in a string is an escape character, but not a "" , the real string of the path is "c:(f)iles(s)ample.txt", so the replace function will not find the "".
  
  – Drake Wu - MSFT
  Mar 8 at 6:07
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Instead of path.replace, why not initialize path as C:\files\sample.txt ?
  
  – Sailesh D
  Mar 8 at 6:08
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  end user is not aware about computer field they can just copy the file path and paste so it could create problems further.
  
  – lalit Kohli
  Mar 8 at 6:18
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  You don't need to double up on backslashes in runtime data, only in compile-time literals.
  
  – Remy Lebeau
  Mar 8 at 6:20
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  To be not confused with char escaping use the special form of defining string liberals that disables char escaping: file.open(R"(c:filessample.txt)");
  
  – S.M.
  Mar 8 at 6:37
  

  
  
  
  

add a comment | 

I am trying to read file path from user as command line in simple format
ex:

path="c:filessample.txt"

but when trying to access using file.open("c:filessample.txt");
file not found.

so i used path.replace(path.begin(),path.end(),"\","\\") for it to change to \ but its not working.

Help me!!

c++ string

share|improve this question

edited Mar 8 at 5:48

Ansi

19138

asked Mar 8 at 5:42

lalit Kohlilalit Kohli

11

path="c:filessample.txt"

share|improve this question

edited Mar 8 at 5:48

Ansi

19138

asked Mar 8 at 5:42

lalit Kohlilalit Kohli

11

share|improve this question

edited Mar 8 at 5:48

Ansi

19138

asked Mar 8 at 5:42

lalit Kohlilalit Kohli

11

edited Mar 8 at 5:48

Ansi

19138

edited Mar 8 at 5:48

Ansi

19138

asked Mar 8 at 5:42

lalit Kohlilalit Kohli

11

asked Mar 8 at 5:42

lalit Kohlilalit Kohli

11

1 Answer
1

active

oldest

votes

0

As you seem to know

path="c:filessample.txt";

is incorrect, it should be

path="c:\files\sample.txt";

(or forward slashes work as well)

path="c:/files/sample.txt";

But this is also incorrect

path="c:filessample.txt";
path.replace(path.begin(),path.end(),"\","\\");

The second line replaces all the single backslashes with double backslashes, but there are no single backslashes in your original string.

f is an escape sequence for the form feed character, and s not even a legal character sequence.

Escape sequences are used in string literals to denote characters which would otherwise be hard to write. For instance you cannot easily put " in a string literal because it would end the string, so the escape sequence " exists to let you do this. Similarly since the backslash character is used to start an escape sequence, the escape sequence \ stands for the backslash character itself.

These rules apply to string literals only, if you are reading a string from the user then there is no need to replace the backslashes with double backslashes, that makes no sense because single backslashes are what you want in a file path. It's just that the way to get single backslashes in a string literal is to write double backslashes.

share|improve this answer

edited Mar 8 at 6:49

answered Mar 8 at 6:43

johnjohn

38.4k12848

add a comment | 

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0

As you seem to know

path="c:filessample.txt";

is incorrect, it should be

path="c:\files\sample.txt";

(or forward slashes work as well)

path="c:/files/sample.txt";

But this is also incorrect

path="c:filessample.txt";
path.replace(path.begin(),path.end(),"\","\\");

The second line replaces all the single backslashes with double backslashes, but there are no single backslashes in your original string.

f is an escape sequence for the form feed character, and s not even a legal character sequence.

Escape sequences are used in string literals to denote characters which would otherwise be hard to write. For instance you cannot easily put " in a string literal because it would end the string, so the escape sequence " exists to let you do this. Similarly since the backslash character is used to start an escape sequence, the escape sequence \ stands for the backslash character itself.

These rules apply to string literals only, if you are reading a string from the user then there is no need to replace the backslashes with double backslashes, that makes no sense because single backslashes are what you want in a file path. It's just that the way to get single backslashes in a string literal is to write double backslashes.

share|improve this answer

edited Mar 8 at 6:49

answered Mar 8 at 6:43

johnjohn

38.4k12848

add a comment | 

0

As you seem to know

path="c:filessample.txt";

is incorrect, it should be

path="c:\files\sample.txt";

(or forward slashes work as well)

path="c:/files/sample.txt";

But this is also incorrect

path="c:filessample.txt";
path.replace(path.begin(),path.end(),"\","\\");

The second line replaces all the single backslashes with double backslashes, but there are no single backslashes in your original string.

f is an escape sequence for the form feed character, and s not even a legal character sequence.

Escape sequences are used in string literals to denote characters which would otherwise be hard to write. For instance you cannot easily put " in a string literal because it would end the string, so the escape sequence " exists to let you do this. Similarly since the backslash character is used to start an escape sequence, the escape sequence \ stands for the backslash character itself.

These rules apply to string literals only, if you are reading a string from the user then there is no need to replace the backslashes with double backslashes, that makes no sense because single backslashes are what you want in a file path. It's just that the way to get single backslashes in a string literal is to write double backslashes.

share|improve this answer

edited Mar 8 at 6:49

answered Mar 8 at 6:43

johnjohn

38.4k12848

add a comment | 

As you seem to know

path="c:filessample.txt";

is incorrect, it should be

path="c:\files\sample.txt";

(or forward slashes work as well)

path="c:/files/sample.txt";

But this is also incorrect

path="c:filessample.txt";
path.replace(path.begin(),path.end(),"\","\\");

The second line replaces all the single backslashes with double backslashes, but there are no single backslashes in your original string.

f is an escape sequence for the form feed character, and s not even a legal character sequence.

Escape sequences are used in string literals to denote characters which would otherwise be hard to write. For instance you cannot easily put " in a string literal because it would end the string, so the escape sequence " exists to let you do this. Similarly since the backslash character is used to start an escape sequence, the escape sequence \ stands for the backslash character itself.

These rules apply to string literals only, if you are reading a string from the user then there is no need to replace the backslashes with double backslashes, that makes no sense because single backslashes are what you want in a file path. It's just that the way to get single backslashes in a string literal is to write double backslashes.

share|improve this answer

edited Mar 8 at 6:49

answered Mar 8 at 6:43

johnjohn

38.4k12848

path="c:filessample.txt";

path="c:\files\sample.txt";

path="c:/files/sample.txt";

path="c:filessample.txt";
path.replace(path.begin(),path.end(),"\","\\");

share|improve this answer

edited Mar 8 at 6:49

answered Mar 8 at 6:43

johnjohn

38.4k12848

answered Mar 8 at 6:43

johnjohn

38.4k12848

answered Mar 8 at 6:43

johnjohn

38.4k12848