template type problem in msvc. and more

Bogdan Sintoma · *nix forums beginner Joined: 14 Mar 2005 Posts: 10

icedac wrote:

icedac · *nix forums beginner Joined: 02 Feb 2005 Posts: 1

I have some questions about template and c++ itself.

/////////////////////////////////////////////////////////////////////////
q1) see follow c++ code, and compile. it's works only IntelC++8.1 but
VC71.
Do you know why? Which compiler's activity is C++STANDARD? And I wanna
be
feed back some explain. Smile

//-----------------------------------------------------------------------
//
// COMPILER_TEST!,
//
// a) VC71 fail to compile
// b) IC81 OK
//
//-----------------------------------------------------------------------
template < typename MY_TYPE_ >
class TestClass1
{
public:
typedef int TEST_TYPE;
};

template < typename MY_TYPE_ >
class TestClass2
{
public:
typedef MY_TYPE_ MY_TYPE;
typedef TestClass1<MY_TYPE> TEST_CLASS1;
typedef TestClass2<MY_TYPE> TEST_CLASS2;
typedef typename TEST_CLASS1::TEST_TYPE TEST_TYPE1;

//typename TestClass2<MY_TYPE_>:: // this make msvc happy, but I dont
know why!
TEST_TYPE1 TestMethod1();

//
// consequently,
// a) typename TestClass2<MY_TYPE_>::TEST_TYPE1
// and
// b) TEST_TYPE1
//
// is different type! why? its the same type!
//
// i think its result due to the "typename"
//

void TestMethod2( TEST_TYPE1 a );
};

/* this will emit error in MSVC */
template < typename MY_TYPE_ >
typename TestClass2<MY_TYPE_>::TEST_TYPE1 /* return type; return type
can not use types in TestClass2
it have to specify TestClass2 scope to compile*/
TestClass2<MY_TYPE_>::TestMethod1()
{
printf( "typename TestClass2<MY_TYPE_>::TEST_TYPE1
TestClass2<MY_TYPE_>::TestMethod1() - called.\r\n" );
return 0;
}

/* this is ok */
template < typename MY_TYPE_ >
void
TestClass2<MY_TYPE_>::TestMethod2(
//typename TestClass2<MY_TYPE_>:: //this var is on scope of
TestClass2, it can use types in TestClass2
TEST_TYPE1 a
)
{
return 0;
}

void test_2()
{
TestClass2<int> a;
a.TestMethod1();
}
//---------END_OF_CODE

/////////////////////////////////////////////////////////////////////////
q2)
code:
//-- start of code
class TestCalss3
{
public:
typedef int TEST_TYPE3;
TEST_TYPE3 TestMethod3( TEST_TYPE3 a );
};

inline
TestCalss3::TEST_TYPE3 TestCalss3::TestMethod3( TEST_TYPE3 a )
{
return 1;
}
//-- end of code

Why c++ standard make difference between 'RETURN type' and 'ARGUMENT
type'?
I think 'new code1' or 'new code2' is looks better. Or I omit some
important point(s) about c++ design or compiler design?

//-- new code1
inline
TEST_TYPE3 TestCalss3::TestMethod3( TEST_TYPE3 a )
{
return 1;
}
//-- new code2
inline
TestCalss3::TEST_TYPE3 TestCalss3::TestMethod3( TestCalss3::TEST_TYPE3
a )
{
return 1;
}
//--

/////////////////////////////////////////////////////////////////////////
I'll expect good reply. Thank you in advance.
ps excuse my BAD english Smile

I'm not native writer :0

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