initialization of built in types in templates

[Gernot Frisch]

// THIS CODE:
template<class T> class C
{
public:
C()
{
T t;
data[0] = t;
}


T data[5];
};


int main(int, char**)
{
C<double> c;
return 0;
}

// END CODE

yields error: local variable 't' used without being initialized.
What can I do to make it work with built in variables, initialized as
0?

Must I really specialize for every built in type?

 

[Ian Collins]

// THIS CODE:
template<class T> class C
{
public:
C()
{
T t;
data[0] = t;
}


T data[5];
};


int main(int, char**)
{
C<double> c;
return 0;
}

// END CODE

yields error: local variable 't' used without being initialized.
What can I do to make it work with built in variables, initialized as
0?

What do you want it to do? Is data[0] = T(); what you want?

 

[Kai-Uwe Bux]

// THIS CODE:
template<class T> class C
{
public:
C()
{
T t;
data[0] = t;

What about ditching the variable t altogether:

data[0] = T();

}


T data[5];
};


int main(int, char**)
{
C<double> c;
return 0;
}

// END CODE

yields error: local variable 't' used without being initialized.
What can I do to make it work with built in variables, initialized as
0?

Must I really specialize for every built in type?

No.


Best

Kai-Uwe Bux

 

[Jim Langston]

// THIS CODE:
template<class T> class C
{
public:
C()
{
T t;

T t();

data[0] = t;

Although you could just do it here:
data[0] = t();

}


T data[5];
};


int main(int, char**)
{
C<double> c;
return 0;
}

// END CODE

yields error: local variable 't' used without being initialized.
What can I do to make it work with built in variables, initialized as 0?

Must I really specialize for every built in type?

 

[Jim Langston]

// THIS CODE:
template<class T> class C
{
public:
C()
{
T t;

T t();

data[0] = t;

Although you could just do it here:
data[0] = t();

er,
data[0] = T();
is what I meant.

}


T data[5];
};


int main(int, char**)
{
C<double> c;
return 0;
}

// END CODE

yields error: local variable 't' used without being initialized.
What can I do to make it work with built in variables, initialized as 0?

Must I really specialize for every built in type?

 

[Gernot Frisch]

What can I do to make it work with built in variables, initialized
as
0?

What do you want it to do? Is data[0] = T(); what you want?

Doh! thank you

 

[Gernot Frisch]

T t();

didn't work for <unsigned char>. It's trying to assign a function
then.
Ian's solution did it, though.
Thx for quick response.

 

[dasjotre]

didn't work for <unsigned char>. It's trying to assign a function
then.

not just for unsigned char.

T t();

declares function T (*)(void).

you either do
T t = T();
data[0] = t;

or
data[0] = T();

Ian's solution did it, though.
Thx for quick response.

check boost::value_intialized if you have to do
the same for non POD types.

regards

DS

 

[Marcus Kwok]

T t();

This will declare a function called 't' that takes no parameters and
returns a T.

data[0] = t;

Although you could just do it here:
data[0] = t();

data[0] = T(); as others have mentioned (including yourself in a later
post).