C ++定义类成员结构并在成员函数中返回它 [英] C++ define class member struct and return it in a member function

问题描述

我的目标是像这样的课程：

My goal is a class like:

class UserInformation
{
public:
    userInfo getInfo(int userId);
private:
    struct userInfo
    {
        int repu, quesCount, ansCount;
    };
    userInfo infoStruct;
    int date;
};

userInfo UserInformation::getInfo(int userId)
{
    infoStruct.repu = 1000; 
    return infoStruct;
}

但是编译器给出了错误，它定义了公共函数 getInfo（int）返回类型 userInfo 不是类型名称。

but the compiler gives error that in defintion of the public function getInfo(int) the return type userInfo is not a type name.

推荐答案

您需要更改 UserInformation 成员的顺序，并放入 struct UserInfo 上方声明 getInfo 。编译器抱怨说，它无法计算 getInfo 的签名，因为尚未看到其返回类型的定义。

You need to change the order of the members of UserInformation and put struct UserInfo above the declaration of getInfo. The compiler complains that it can't work out the signature for getInfo because it hasn't seen the definition of its return type yet.

此外，如果要从函数返回结构，则该结构的类型必须对调用者可见。因此，您还需要将结构公开。

Also, if you are returning a struct from the function the type of the struct must be visible to the callers. So you need to make the struct public as well.

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