How to properly use a header file to be a complete class?

Question

(Beginner programmer..) I'm following the style of a header file that worked fine, but I'm trying to figure out how I keep getting all of these errors when I compile. I am compiling with g++ in Cygwin.

Ingredient.h:8:13: error: expected unqualified-id before ‘)’ token
Ingredient.h:9:25: error: expected ‘)’ before ‘n’
Ingredient.h:19:15: error: declaration of ‘std::string <anonymous class>::name’
Ingredient.h:12:14: error: conflicts with previous declaration ‘std::string<anonymous class>::name()’
Ingredient.h:20:7: error: declaration of ‘int <anonymous class>::quantity’
Ingredient.h:13:6: error: conflicts with previous declaration ‘int<anonymous class>::quantity()’
Ingredient.h: In member function ‘std::string<anonymous class>::name()’:
Ingredient.h:12:30: error: conversion from ‘<unresolved overloaded function type>’ to non-scalar type ‘std::string’ requested
Ingredient.h: In member function ‘int<anonymous class>::quantity()’:
Ingredient.h:13:25: error: argument of type ‘int (<anonymous class>::)()’ does not match ‘int’
Ingredient.h: At global scope:
Ingredient.h:4:18: error: an anonymous struct cannot have function members
Ingredient.h:21:2: error: abstract declarator ‘<anonymous class>’ used as declaration

And here is my class header file...

#ifndef Ingredient
#define Ingredient

class Ingredient {

public:
  // constructor
    Ingredient() : name(""), quantity(0) {} 
    Ingredient(std::string n, int q) : name(n), quantity(q) {}

  // accessors
    std::string name() { return name; }
    int quantity() {return quantity; }

  // modifier

private:
  // representation
  std::string name;
  int quantity;
};

#endif

I am confused by these errors and don't really know what I am doing wrong concerning the implementation of the class..

Answer 1

That's a funny one. You are essentially killing your class name by #define Ingredient - all occurrences of Ingredient will be erased. This is why include guards generally take the form of #define INGREDIENT_H.

You are also using name both for the member and the getter function (probably an attempt to translate C#?). This is not allowed in C++.

Answer 2

How about look on errors? variables and functions can't have same names. And include guard should never names such as class.

#ifndef INGREDIENT_H
#define INGREDIENT_H

class Ingredient {

public:
  // constructor
    Ingredient() : name(""), quantity(0) {} 
    Ingredient(std::string n, int q) : name(n), quantity(q) {}

  // accessors
    std::string get_name() const { return name; }
    int get_quantity() const {return quantity; }

  // modifier

private:
  // representation
  std::string name;
  int quantity;
};

#endif