在类中声明结构

Question

I created a class called Text , and one of its members is a std::vector of Pal_freq , a struct declared inside the class .

I am getting those errors:

error: 'Pal_freq' does not name a type bool criteri (const Pal_freq& p1, const Pal_freq& p2);

error: 'Pal_freq' does not name a type bool criteri (const Pal_freq& p1, const Pal_freq& p2);

error: 'Pal_freq' was not declared in this scope vector consultar_taula_freq();

error: template argument 1 is invalid vector consultar_taula_freq();

Here is the code:

class Text {
 public:

  struct Pal_freq {
  int freq;
  string pal;
  };

  vector <Pal_freq> taula;
};

Answer 1

The error messages are not coming from the tiny piece of ode you showed (the definition of the struct), they are coming from other pieces of code that you didn't show us (ie where you try to use the nested struct).

Because it is declared inside Text you need to qualify its name when you refer to it outside the scope of Text , so you need to refer to it as Text::Pal_freq eg

bool criteri (const Text::Pal_freq& p1, const Text::Pal_freq& p2);

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