Does not name type c++ error?

Does not name type c++ error?

7 Answers. When the compiler compiles the class User and gets to the MyMessageBox line, MyMessageBox has not yet been defined. The compiler has no idea MyMessageBox exists, so cannot understand the meaning of your class member. You need to make sure MyMessageBox is defined before you use it as a member.

Does not name a type error in Qt?

This is a very frustrating error message in Qt Creator: ‘XYZ’ does not name a type . This usually means that there is an error in the class XYZ that prevents the compiler from generating the type, but there are no additional hints as to what went wrong.

How does forward declaration Work C++?

A forward declaration tells the compiler about the existence of an entity before actually defining the entity. Forward declarations can also be used with other entity in C++, such as functions, variables and user-defined types.

What happens if a class does not have a name?

What will happen if a class is not having any name? It cannot have a destructor. It cannot have a constructor. It is not allowed.

What is an undefined reference in C++?

An “Undefined Reference” error occurs when we have a reference to object name (class, function, variable, etc.) in our program and the linker cannot find its definition when it tries to search for it in all the linked object files and libraries.

Which does not name a type inside class?

This was throwing the same compiler error message mentioning that Class A does not name a type . There was no circular dependency in my case. So, be careful while naming classes and declaring enums (which might be visible, imported and used externally in other files) in C++.

What is the meaning of typedef struct in C?

The C language contains the typedef keyword to allow users to provide alternative names for the primitive (e.g.,​ int) and user-defined​ (e.g struct) data types. Remember, this keyword adds a new name for some existing data type but does not create a new type.

When can you use forward declaration C++?

When can I use a forward declaration in C/C++? In C++ the forward declaration lets the code following the declaration know that there is are classes with the name Person. This satisfies the compiler when it sees these names used. Later the linker will find the definition of the classes.

Why does C++ need forward declaration?

A forward declaration allows us to tell the compiler about the existence of an identifier before actually defining the identifier. In the case of functions, this allows us to tell the compiler about the existence of a function before we define the function’s body.

How to fix does not name type error in C + +?

If I use the include header file, the errors don’t go away. If I combine the vector header file and add std to each vector, I get template argument 1 and 2 is invalid, string was not declared in this scope, suggestive alternative is std::string.

When do you name a type in C + +?

Although possibly unrelated to OP’s original question… this is an error I just had and shows how this error could occur. When you define a type in a C++ class and you return it, you need to specify the class in which the type belongs. ClassName::TypeName ClassName::GetData () {…} TypeName ClassName::GetData () {…}

When to use node type instead of node type?

From what I’ve read, it seems the errors come about when an object is referenced that isn’t already defined, but I’m not really seeing how I’ve made that error. The error is correct: there is no Node type anywhere in your program. However there is a LinkedList ::Node type. Use it instead.

When to replace type name in Arduino compiler?

Since your class MyLiquidCrystal is declared inside a namespace ( MyProject ), you need to use the full type name to use it outside of that namespace. In your case, you should replace: This will tell the compiler that the whole content of MyProject namespace should be imported to the global namespace, which will allow direct access to its content.