C++生成key-value键值的三种方式总结

#include <iostream>
#include <vector>
#include <map>
int main() {
  std::map<std::string, std::string> keyValueMap;
  //v1.0
  keyValueMap = { {"name", "张三"}, {"age", "20"}, {"country", "中国"} };
  // 遍历map并打印键值对
  for (const auto& pair : keyValueMap) {
    std::cout << pair.first << ": " << pair.second << std::endl;
  }
  std::cout << std::endl;
  keyValueMap.clear();
  //v2.0
  keyValueMap.insert({"name","李四"});
  keyValueMap.insert({"age","18"});
  keyValueMap.insert({"country","China"});
  //遍历map并打印键值对
  for (const auto& pair : keyValueMap) {
    std::cout << pair.first << ": " << pair.second << std::endl;
  }
  std::cout << std::endl;
  return 0;
}

#include <iostream>
#include <vector>
#include <map>
int main() {
  //vector + pair
  //v1.0
  std::vector<std::pair<std::string, std::string>> keyValuevt;
  keyValuevt = { {"name", "王五"}, {"age", "22"}, {"country", "中国"} };
  for (const auto& vv : keyValuevt) {
    std::cout << vv.first << ": " << vv.second << std::endl;
  }
  std::cout << std::endl;
  keyValuevt.clear();
  //v2.0
  keyValuevt.push_back({"name","Tom"});
  keyValuevt.push_back({"age","10"});
  keyValuevt.push_back({"countyr","China"});
  for (const auto& vv : keyValuevt) {
    std::cout << vv.first << ": " << vv.second << std::endl;
  }
  return 0;
}

#include <iostream>
#include <vector>
#include <map>
int main() {
  std::vector<std::pair<std::string, std::string>> keyValuevt;
  //vector + make_pair
  //v1.0
  keyValuevt.push_back(std::make_pair("name", "六五"));
  keyValuevt.push_back(std::make_pair("age", "21"));
  keyValuevt.push_back(std::make_pair("country", "中国"));
  for (const auto& vv : keyValuevt) {
    std::cout << vv.first << ": " << vv.second << std::endl;
  }
  std::cout << std::endl;
  keyValuevt.clear();
  //v2.0
  keyValuevt.push_back({"name","Tom"});
  keyValuevt.push_back({"age","10"});
  keyValuevt.push_back({"countyr","China"});
  for (const auto& vv : keyValuevt) {
    std::cout << vv.first << ": " << vv.second << std::endl;
  }
  return 0;
}