Deducing Function Template Arguments

Hello everyone,


Here is my understanding of what Bjarne said in his The C++ Programming Language book. I am not sure whether my understanding is correct? I am somewhat confused about the following statements.

My understanding is,

means if a function call like this,

Code:

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void func(const A a) // A is a specific type

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then compiler can deduce argument type of template function below to A?

Code:

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template <class T> func (T a)

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Bjarne's original statements are,

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C.13.4 Deducing Function Template Arguments

A compiler can deduce a type template argument, T or TT , and a nontype
template argument, I, from a template function argument with a type composed of the following constructs:

Code:

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T const T volatile T
T*  T& T[constant_expression]
type[I]  class_template_name<T> class_template_name<I>
T T<T > T<I > T<>

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thanks in advance,
George

Quote:

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means if a function call like this,

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That's not a function call. That's a head. Add a semicolon, it's a prototype. Add braces, it's an implementation.

Sorry CornedBee,


My bad. :-)

If I change to the following in my original post, do you think my
understanding is correct?

Code:

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const A a; // A is a specific type
func(a); // can deduce T to A.

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Quote:

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Originally Posted by CornedBee

That's not a function call. That's a head. Add a semicolon, it's a prototype. Add braces, it's an implementation.

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regards,
George

Yes, it can. So long as you don't pass unambiguous types, the compiler can deduce the type.

Thanks Elysia,


Question answered.

Quote:

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Originally Posted by Elysia

Yes, it can. So long as you don't pass unambiguous types, the compiler can deduce the type.

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regards,
George