C++ 11三个新特性的简单使用 - std::function、lambda 表达式、智能指针

末蓝、 2022-12-30 10:44 6阅读 0赞

使用Dev C++；先设置Dev C++ 支持 C++ 11；见此文后部；

[https://blog.csdn.net/bcbobo21cn/article/details/111466179][https_blog.csdn.net_bcbobo21cn_article_details_111466179]

### 1 std::function ###

#include <functional>
        #include <iostream>
        
        using namespace std;
        
         int myadd(int a, int b)
         {
           return a+b;
         }
         
         int main()
         {
         	std::function<int(int, int)>func = myadd;
         	cout<<func(4, 7)<<endl;      // 11
         	system("pause");
         	return 0;
         }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70][]

### 2 lambda表达式 ###

#include <functional>
        #include <iostream>
        
        using namespace std;
        
         int main()
         {
    		int xx= 10;
    		auto myf = [xx] (int a) { cout << "hello, world, Lambda,  " << a << ",  " << xx << endl; };		
    		
    		myf(99099);        	
         	system("pause");     	     	
         	return 0;
         }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70 1][]

### 3 智能指针 ###

#include <memory>
        #include <iostream>
        
        using namespace std;
        
         int main()
         {
    		std::shared_ptr<int> p1(new int(99099));
    		std::shared_ptr<std::string> ss(new std::string("AAABBB"));
    		
    		cout << p1 << ",  " << p1.use_count() << endl;
    		cout << ss << ",  " << ss.use_count() << endl;
    
    		auto a1 = std::make_shared<int>(9979);
    		cout << a1 << endl;
    		       	
         	system("pause");     	     	
         	return 0;
         }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70 2][]

[https_blog.csdn.net_bcbobo21cn_article_details_111466179]: https://blog.csdn.net/bcbobo21cn/article/details/111466179
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70]: /images/20221120/9281f7a3e2c4424aa8a3bce50bc9d9ec.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70 1]: /images/20221120/2cb9dab16abb4f3596c3e3963cf2d1ce.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20201224231018441.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24=,size_16,color_FFFFFF,t_70