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Started by luasitdown Feb 1, 2006 at 9:53 AM 6 replies 650+ views

Original Post

Feb 1, 2006 at 9:53 AM


// not work
Mesh * MeshManager::mesh(const std::string meshName)
{
	if ( (  MeshMapIterator iter = m_meshList.find(meshName)  ) != m_meshList.end() )
	{
		return iter->second;
	}
	else
	{
		return 0;
	}
}

// work

Mesh * MeshManager::mesh(const std::string meshName)
{
	if (    m_meshList.find(meshName)    != m_meshList.end() )
	{
                MeshMapIterator iter =  m_meshList.find(meshName);
		return iter->second;
	}
	else
	{
		return 0;
	}
}
// also work
Mesh * MeshManager::mesh(const std::string meshName)
{
	MeshMapIterator iter;
	if ( (  iter = m_meshList.find(meshName)  ) != m_meshList.end() )
	{
		return iter->second;
	}
	else
	{
		return 0;
	}
}

why?

dbzprogrammer

Feb 1, 2006 at 9:59 AM

Is this a compiler or run-time error?

riltniqaz

Feb 1, 2006 at 10:12 AM

Maybe your compiler won't let you declare a variable within an IF statement's parameter?

Quote:
if ( ( MeshMapIterator iter = m_meshList.find(meshName) ) != m_meshList.end() )

Zakwayda

Feb 1, 2006 at 10:18 AM

I don't know what the scope of a variable declared in an 'if' conditional is, but I've never seen that done before; it might not be legal code. In any case, you should post your exact errors when you run into problems, as it will make it easier for people to help you. Also, you might make your std::string arguments references instead of passing by value.

Your last example is probably the best choice of the ones you posted. Assigning within the conditional is legal, but IMO it doesn't make for the clearest code. I'd do it like this:

Mesh* MeshManager::getMesh(const std::string& meshName){    MeshMapIterator iter = m_meshList.find(meshName);    return (iter == m_meshList.end()) ? 0 : iter->second;}

luasitdown

Feb 1, 2006 at 10:29 AM

it is compile error.

it give me 8 compile error.
it said "(" is not correct.
Is empty statement ";" necessary?
undelcaration identity iter
there is a lack of ;
illegal else no match if
.......

Zakwayda

Feb 1, 2006 at 10:38 AM

That wouldn't compile for me either - I can't say for sure, but I don't think that's legal code.

luasitdown

Feb 1, 2006 at 10:46 AM

thanks.

take a look

	Mesh * createMesh( const std::string& filename, const std::string& meshName, D3DDevice* device);// Is the code nice style?  is it commended?		MeshManager::singleton().createMesh( filename, meshName ,m_device)->load();// Is this line  also nice? Do I need the tmp variable or other?	return m_meshList[meshName] = new SkinnedMesh(filename, meshName, device);

xEricx

Feb 1, 2006 at 10:59 AM

I highly doubt that's legal to declare a variable inside ()'s...

#include "stdafx.h"int _tmain(int argc, _TCHAR* argv[]){    if(int Legal = 1)    {    }    (int Illegal = 0);    if((int AlsoIllegal = 1))    {    }    return 0;}

d:\tmp\Test123\Test123.cpp(10) : error C2146: syntax error : missing ')' before identifier 'Illegal'd:\tmp\Test123\Test123.cpp(10) : error C2065: 'Illegal' : undeclared identifierd:\tmp\Test123\Test123.cpp(10) : error C2059: syntax error : ')'d:\tmp\Test123\Test123.cpp(11) : error C2146: syntax error : missing ')' before identifier 'AlsoIllegal'd:\tmp\Test123\Test123.cpp(11) : error C2065: 'AlsoIllegal' : undeclared identifierd:\tmp\Test123\Test123.cpp(11) : error C2059: syntax error : ')'

all you need to do, is remove the ()'s

if(MeshMapIterator iter = m_meshList.find(meshName) != m_meshList.end())

it should work.

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