Thread: Compiler errors

Hey,

These seem like simple compiler errors but I have been unable to figure them out. Here are the errors I am getting:

Code:

5 routeData.h expected init-declarator before '<' token 
5 routeData.h expected `,' or `;' before '<' token 
6 routeData.h expected init-declarator before '<' token 
6 routeData.h expected `,' or `;' before '<' token 
7 routeData.h expected init-declarator before '<' token 
7 routeData.h expected `,' or `;' before '<' token 
8 routeData.h expected init-declarator before '<' token 
8 \routeData.h expected `,' or `;' before '<' token 
20 routeData.h expected `;' before '(' token 
22 routeData.h `iLst' does not name a type

My code is:

Code:

#ifndef ROUTE
#define ROUTE
#include <set>
#include <list>
typedef set<int>		    iSet; // line 5
typedef list<int> 		    iLst; // line 6
typedef set<int>::iterator	iSetPtr; // line 7
typedef list<int>::iterator	iLstPtr; // line 8

using namespace std;

class routeData
{
    public:
	
    	int readRouteData(istream & inSource);
    
    	int distance(int first, int second);
    
    	int distance(iLst route); // line 20
    
    	iLst bestRoute(iLst done, iSet left); // line 22
};

#endif

Make aa a string::size_type, since that is the type returned by length().

or you can take the warning literally and make aa unsigned:

Code:

for(unsigned int aa = 0; aa < temp.length(); aa++)

I am not sure if that is a good practice though.

Originally Posted by cyberfish

or you can take the warning literally and make aa unsigned:

Code:

for(unsigned int aa = 0; aa < temp.length(); aa++)

I am not sure if that is a good practice though.

I'm guessing that would only suppress the warning if string::size_type is actually the same as unsigned int on the given platform (on a 64-bit box they might not be, for example). Also, the former is about the same number of characters to type anyway and is always the correct type.

Originally Posted by Beowolf

Code:

20 routeData.cpp [Warning] comparison between signed and unsigned integer expressions

To clarify:
This is because you're comparing a signed and unsigned integer (which is not possible AFAIK). The compiler will convert both types to either signed or unsigned, not sure which.
To avoid this warning, only compare an unsigned integer to an unsigned and the same to signed. If you have one signed and one unsigned, cast one of them to unsigned/signed so you're comparing two of the same type.

> there would be a good argument for someone implementing that particular compiler to change the size_type to signed.

I'm fairly sure that the Standard guarantees that not only std::size_t but any of the size_type's are always some unsigned integral type, so that's not an option.

Originally Posted by matsp

Yes, and this is only a problem when one of the numbers MAY be signed - if you know for sure that both numbers [despite one of them being signed] can never be (validly) negative, then you can safely ignore the warning.

--
Mats

Or cast one to unsigned so the compiler shuts up