vector find error

[heidik]

Hello everyone

could you please look at the error generated by the below piece of code? It is apparently generated by the IF statement inside the for loop because commenting this IF statement resolves the error.

for ( std::vector<TRS_block>::iterator trs = common_TRS.begin() ; trs < common_TRS.end(); trs++ )
	{
                // error occurs because of this IF statement
		if(std::find( trs_file_as_blocks.begin(), trs_file_as_blocks.end(), *trs ) != trs_file_as_blocks.end())
		{
				
		}
	}

and the error is:

/usr/lib/gcc/x86_64-redhat-linux/4.4.4/../../../../include/c++/4.4.4/bits/stl_algo.h:174: error: no match for ‘operator==’ in ‘__first.__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = mergeTRSLCdata::TRS_block*, _Container = std::vector<mergeTRSLCdata::TRS_block, std::allocator<mergeTRSLCdata::TRS_block> >]() == __val’

Please suggest how to resolve this issue.

Thanks

[jonnin]

Guessing here, because that is pretty convoluted, but it looks like the == operator that we discussed earlier was not visible to the compiler (???) or, if this is another class/project, it boils down to the same thing. Your code is calling the == function behind the scenes and the compiler cannot find an overloaded == function that will work, you need to either supply one (if you have not) or make it visible (there is a design error preventing it from being used) to the compiler.

[Danny]

Just a shot in the dark: try replacing std::vector<TRS_block>::iterator trs
with
std::vector<TRS_block>::const_iterator trs.

[heidik]

Thanks Jonnin and Danny :). Overloading the ==() operator has solved my problem

friend bool operator==(const TRS_block& lhs, const TRS_block& rhs)
{
  return (lhs.TOTALS        == rhs.TOTALS) &&
	 (lhs.TRS_O_SLIP_NO == rhs.TRS_O_SLIP_NO) &&
	 (lhs.raw_contents  == rhs.raw_contents);
}

[Danny]

Great! and I'm glad you used the extern friend option. Your code demonstrates again why it's important to overload symmetric binary operators as external functions, not as member functions.

[heidik]

:)