蓝桥ROS机器人之现代C++学习笔记4.2 无序容器

Posted 2022-04-09 zhangrelay

学习程序如下：

#include <iostream>
#include <string>
#include <unordered_map>
#include <map>

int main() 
    // initialized in same order
    std::unordered_map<int, std::string> u = 
        1, "1",
        3, "3",
        2, "2"
    ;
    std::map<int, std::string> v = 
        1, "1",
        3, "3",
        2, "2"
    ;
    
    // iterates in the same way
    std::cout << "std::unordered_map" << std::endl;
    for( const auto & n : u)
        std::cout << "Key:[" << n.first << "] Value:[" << n.second << "]\\n";
    
    std::cout << std::endl;
    std::cout << "std::map" << std::endl;
    for( const auto & n : v)
        std::cout << "Key:[" << n.first << "] Value:[" << n.second << "]\\n";

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查资料☞无序：获取性能提升。 

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