C + + prevents redefinition

There are 2 ways to prevent redefinition:

The first type:

#ifndef My_head_h_included#define my_head_h_included#endif//my_head_h_included

This scenario is a very common scenario that can be passed by various Ides.

The second type:

#pragma once

This scheme, meaning under which all definitions are defined only Once. The second method is relatively new, and some older Ides cannot be passed cheaply.

This article is from the "better_power_wisdom" blog, make sure to keep this source http://aonaufly.blog.51cto.com/3554853/1920926

C + + prevents redefinition