P
Peter Olcott
Does C++ have anything like this?
I
Ian Collins
Like what?Peter said:
P
Peter Olcott
Does C++ have anything that uses something like a
std::string for text file input?
std::string for text file input?
I
Ian Collins
Peter Olcott wrote:
Please don't top-post.
std::string s;
std::cin >> s;
Please don't top-post.
std::string s;
std::cin >> s;
O
osmium
"Ian Collins" write:
Based on the OPs question, I suspect he wants to change cin to the name of a
file opened for reading.
Based on the OPs question, I suspect he wants to change cin to the name of a
file opened for reading.
T
Thomas J. Gritzan
osmium said:
You mean like:
std::string filename = "...";
std::ifstream in(filename.c_str());
std::string s;
in >> s;
J
Juha Nieminen
osmium said:
Another possibility is that he wants to read a string as if it was
an input stream.
If that's the case, then std::stringstream is the answer.
J
Jim Langston
Peter Olcott said:
file input using std::string.
It depends on what you mean, like others have said. Do you want to input to
a std::string, or read from a std::string?
Input to a std::string: (untested code)
#include <istream>
#include <string>
int main()
{
std::ifstream Input("Myfile.ext");
std::string Data;
if ( std::getline( Input, Data ) )
// Data now contains one line of text from the file. (deliminated by
'\n')
if ( Input >> Data )
// Data now contains one word form the file (delimited by white space)
}
Read from a std::string:
#include <sstream>
#include <string>
int main()
{
std::string MyString( "This is some text\nJust to show an example" );
std::stringstream MyStream;
MyStream << MyString;
std::string Data;
if ( std::getline( MyStream, Data ) )
// Data should now contain "This is some text"
if ( MyStream >> Data )
// Data should now contain "Just"
}
P
Peter Olcott
Jim Langston said:
Yes this is what I was talking about, I need text delimited
by lines.
What is the "if" for ???
J
James Kanze
[...]
To test whether the input succeeded or not. std::getline (like
the << operators) returns a reference to the stream it read;
when used in a condition, the stream will act true if there has
been no error to date, and false if there was some sort of error
(typically, in this case, due to trying to read beyond the end
of file).
P
Peter Olcott
[...]
To test whether the input succeeded or not. std::getline
(like
the << operators) returns a reference to the stream it read;
when used in a condition, the stream will act true if there
has
been no error to date, and false if there was some sort of
error
(typically, in this case, due to trying to read beyond the
end
of file).
So it would typically be written like this?
while ( std::getline( Input, Data ) )
;
--
James Kanze (GABI Software)
email:[email protected]
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J
James Kanze
Well, the loop typically won't be empty
. But yes, that isthe usual idiom for reading an entire file line by line.