Ex.7.53 will not compile under the C++14 standard

[CodingHare]

Exercise information

Exercise 7.53: Define your own version of Debug.

Question or Bug

If you're using C++ 14(or higher) to compile the answer, the any() function, which is defined as:

constexpr bool any() {return hw || io || other; } (line 16)

must be written in:

constexpr bool any() const {return hw || io || other; }

in order to claim itself a const member function. Otherwise the compiler will complain:

error: passing ‘const Debug’ as ‘this’ argument discards qualifiers [-fpermissive]

i hope this helps!

Ref: Difference between constexpr and const

See the B section in the first answer.

Enviroment information

• System: :centos 7.2
• Compiler version/IDE: : g++ 11 & g++ 14