// File: Lab13Frac.h
#include <iostream>
using namespace std;
#ifndef "Lab13Frac.h"
#define "Lab13Frac.h"
// prototpes
#endif
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Jerry Coffin
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booby
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Please format your code. – In silico Apr 28 '10 at 23:45
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Type in 4 spaces before each line of code. – In silico Apr 28 '10 at 23:49
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You format code by selecting it, then clicking the "101010" button. – Jerry Coffin Apr 28 '10 at 23:49
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Which inserts 4 spaces before each line, formatting it at code. Also, put *everything* inside the header guards, including includes. And **don't use `using namespace`!** Especially in a header. – GManNickG Apr 28 '10 at 23:51
2 Answers
7
The identifier should not be in quotes. Also, it should be in all caps by convention.
// File: Lab13Frac.h
#ifndef LAB13FRAC_H
#define LAB13FRAC_H
#include <iostream>
using namespace std;
// The above line is not recommended in header files
// because it may cause namespace collisions.
// See http://www.parashift.com/c++-faq-lite/coding-standards.html#faq-27.5
// Prototypes
#endif
In silico
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1Depending on coding style, it's also possible to write (for example) `#ifndef _LAB13FRAC_H_ ... ` and sometimes `#endif // _LAB13FRAC_H_` – M. Williams Apr 28 '10 at 23:51
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2@Kotti: Except those identifiers are reserved for the compiler. (Any name starting with an underscore followed by another underscore or capital letter are reserved.) – GManNickG Apr 28 '10 at 23:52
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1@GMan Know about the double underscore, but it's the first time when I've heard about `_X....` being reserved. Could you point to some docs to read? – M. Williams Apr 28 '10 at 23:55
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@Kotti, See C++0X FCD 17.6.3.3.2.1: Certain sets of names and function signatures are always reserved to the implementation: — Each name that contains a double underscore _ _ or begins with an underscore followed by an uppercase letter (2.12) is reserved to the implementation for any use. — Each name that begins with an underscore is reserved to the implementation for use as a name in the global namespace. – Nathan Ernst Apr 29 '10 at 00:01
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@Kotti: http://stackoverflow.com/questions/228783/what-are-the-rules-about-using-an-underscore-in-a-c-identifier/228797#228797 – GManNickG Apr 29 '10 at 00:01
1
Here's how I would do that
// File: Lab13Frac.h
#ifndef LAB13FRAC_H
#define LAB13FRAC_H
#include <iostream>
using namespace std; //You shouldn't do this anyway...
// prototpes
#endif //LAB13FRAC_H
You can't use a string as an identifier, use a literal as if it is a variable name.
Also, you should put a comment next to #endif to tell who reads what you are #endifing
Federico klez Culloca
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