#include <fstream.h>
int mapFile[2000];
int main()
{
ifstream map("map.ar", ios::app);
map >> mapFile;
map.close();
return 0;
}
Why wont my file be copied into an array?
December 25, 2002 05:02 PM
this is isnt the actual code but this is basically what i want it to do at the moment:
Now like i said that isnt the actual code but its the only relevent part of my question, basically the compiler says:
error C2679: binary ''>>'' : no operator defined which takes a right-hand operand of type ''int [2000]'' (or there is no acceptable conversion)
it works fine if i use a standard int but then what i wanted to do wouldnt work properly. I need to be able to call every single coord in the file: mapFile[0], mapFile[1] etc. Anyone know a way to fix this?
163
December 25, 2002 05:58 PM
Baaaaad idea. You generally shouldn''t use the >> operator of ifstreams.
For single char input you can use the get member function:
There also is a getline member function.
There is a chapter about iostreams in volume 2 of "Thinking in C++", which you can download at www.bruceeckel.com
"Reality is merely an illusion, albeit a very persistent one." (Albert Einstein)
My Homepage
For single char input you can use the get member function:
int i = 0;while(map.get(mapFile[i])) i++; There also is a getline member function.
There is a chapter about iostreams in volume 2 of "Thinking in C++", which you can download at www.bruceeckel.com
"Reality is merely an illusion, albeit a very persistent one." (Albert Einstein)
My Homepage
---Just trying to be helpful.Sebastian Beschkehttp://randomz.heim.at/
December 26, 2002 07:24 AM
thx very mutch, my book and cprogrammer.com both suggested what i did in the first place which oveously is a error.
164
December 26, 2002 04:39 PM
quote: Original post by randomZ
Baaaaad idea. You generally shouldn't use the >> operator of ifstreams.
Oh? Why not?
If you're comfortable with the stl and more modern use of input streams you could do something like this to read in a file of ints:
#include <vector>#include <algorithm>#include <fstream>#include <iostream>std::vector<int> mapFile;int main(int argv, char ** argv){ std::ifstream map("map.ar"); std::copy(std::istream_iterator<int>(map), std::istream_iterator<int>(), std::back_inserter(mapFile)); return 0;} Oh and to answer the question of why the original posted code doesn't work...
The code "map >> mapFile" is calling a function. You could read it as "map.sendInputTo(mapFile)" or something like that. There are overloaded versions of the function for various built-in types like int, float, double, and string. Their signatures would be like (these might not be 100% accurate):
istream& istream::operator >> (int someInt);
istream& istream::operator >> (float someFloat);
istream& istream::operator >> (double someDouble);
istream& istream::operator >> (string someString);
There is no overloaded version for arrays of ints, which would look like this:
istream& istream::operator >> (int * someIntArray);
There isn't because the function couldn't possibly know how large someIntArray is and might write past its bounds.
[edited by - Dobbs on December 26, 2002 5:58:38 PM]
804
December 26, 2002 04:47 PM
try:
<inputstream>.getline( buffer, sizeof(buffer), ios::EOF );
or whatever to describe EOF.
.lick
[edited by - Pipo DeClown on December 26, 2002 5:47:34 PM]
<inputstream>.getline( buffer, sizeof(buffer), ios::EOF );
or whatever to describe EOF.
.lick
[edited by - Pipo DeClown on December 26, 2002 5:47:34 PM]
This topic is closed to new replies.
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