how to turn a cpp file into a .h and .cpp file code example
Example 1: what is a header in c++
// my_class.h
#ifndef MY_CLASS_H // include guard
#define MY_CLASS_H
namespace N
{
class my_class
{
public:
void do_something();
};
}
#endif /* MY_CLASS_H */
Example 2: what is a header in c++
// sample.h
#pragma once
#include <vector> // #include directive
#include <string>
namespace N // namespace declaration
{
inline namespace P
{
//...
}
enum class colors : short { red, blue, purple, azure };
const double PI = 3.14; // const and constexpr definitions
constexpr int MeaningOfLife{ 42 };
constexpr int get_meaning()
{
static_assert(MeaningOfLife == 42, "unexpected!"); // static_assert
return MeaningOfLife;
}
using vstr = std::vector<int>; // type alias
extern double d; // extern variable
#define LOG // macro definition
#ifdef LOG // conditional compilation directive
void print_to_log();
#endif
class my_class // regular class definition,
{ // but no non-inline function definitions
friend class other_class;
public:
void do_something(); // definition in my_class.cpp
inline void put_value(int i) { vals.push_back(i); } // inline OK
private:
vstr vals;
int i;
};
struct RGB
{
short r{ 0 }; // member initialization
short g{ 0 };
short b{ 0 };
};
template <typename T> // template definition
class value_store
{
public:
value_store<T>() = default;
void write_value(T val)
{
//... function definition OK in template
}
private:
std::vector<T> vals;
};
template <typename T> // template declaration
class value_widget;
}