c++ - Can't access variable in template base class -

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• accessing inherited variable templated parent class 2 answers

i want access protected variable in parent class, have following code , compiles fine:

class base { protected:     int a; };  class child : protected base { public:     int b;     void foo(){         b = a;     } };  int main() {     child c;     c.foo(); } 

ok, want make templated. changed code following

template<typename t> class base { protected:     int a; };  template <typename t> class child : protected base<t> { public:     int b;     void foo(){         b = a;     } };  int main() {     child<int> c;     c.foo(); } 

and got error:

test.cpp: in member function ‘void child<t>::foo()’: test.cpp:14:17: error: ‘a’ not declared in scope              b = a;                  ^ 

is correct behavior? what's difference?

i use g++ 4.9.1

hehe, favourite c++ oddity!

this work:

void foo() {    b = this->a; //     ^^^^^^ } 

unqualified lookup doesn't work here because base template. that's way is, , comes down highly technical details how c++ programs translated.