C++中 vector ，list ，set，map的互相转换

最新推荐文章于 2023-05-24 10:27:09 发布

原创最新推荐文章于 2023-05-24 10:27:09 发布 · 4.5k 阅读

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CC 4.0 BY-SA版权

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#c++ #算法 #c语言

该程序展示了如何在C++中进行容器之间的转换，包括从vector到list，list到set，set回转到vector，以及map的键和值分别转换为vector和list，最后再重建为map。

#include <iostream>
#include <vector>
#include <list>
#include <set>
#include <map>

int main() {
  // 创建 vector
  std::vector<int> vec {1, 2, 3};

  // vector 转换为 list
  std::list<int> lst(vec.begin(), vec.end());

  // list 转换为 set
  std::set<int> st(lst.begin(), lst.end());

  // set 转换为 vector
  std::vector<int> vec2(st.begin(), st.end());

  // 创建 map
  std::map<std::string, int> mp {
    {"apple", 1},
    {"banana", 2},
    {"cherry", 3}
  };

  // 将 map 的键转换为 vector
  std::vector<std::string> keys;
  for (const auto& kv : mp) {
    keys.push_back(kv.first);
  }

  // 将 map 的值转换为 list
  std::list<int> values;
  for (const auto& kv : mp) {
    values.push_back(kv.second);
  }

  // 将 vector 和 list 转换为 map
  std::map<std::string, int> mp2;
  auto key_iter = keys.begin();
  auto value_iter = values.begin();
  while (key_iter != keys.end() && value_iter != values.end()) {
    mp2[*key_iter] = *value_iter;
    key_iter++;
    value_iter++;
  }

  // 输出结果
  std::cout << "vec: ";
  for (const auto& x : vec) {
    std::cout << x << " ";
  }
  std::cout << std::endl;

  std::cout << "lst: ";
  for (const auto& x : lst) {
    std::cout << x << " ";
  }
  std::cout << std::endl;

  std::cout << "st: ";
  for (const auto& x : st) {
    std::cout << x << " ";
  }
  std::cout << std::endl;

  std::cout << "vec2: ";
  for (const auto& x : vec2) {
    std::cout << x << " ";
  }
  std::cout << std::endl;

  std::cout << "mp: ";
  for (const auto& kv : mp) {
    std::cout << "(" << kv.first << ", " << kv.second << ") ";
  }
  std::cout << std::endl;

  std::cout << "keys: ";
  for (const auto& x : keys) {
    std::cout << x << " ";
  }
  std::cout << std::endl;

  std::cout << "values: ";
  for (const auto& x : values) {
    std::cout << x << " ";
  }
  std::cout << std::endl;

  std::cout << "mp2: ";
  for (const auto& kv : mp2) {
    std::cout << "(" << kv.first << ", " << kv.second << ") ";
  }
  std::cout << std::endl;

  return 0;
}