使用 std::sort 比较函数对相应的其他向量元素进行排序[重复]

Question

我有 2 个向量，一个是 int32_t 类型的向量，它对应于学生的年龄，另一个是 std::string 类型的向量，它对应于学生的姓名。我想根据年龄（降序）对学生进行排序，并在学生姓名列表中反映排序变化。

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>


void print(const std::vector<int32_t>& student_age_list, const std::vector<std::string>& student_name_lsit) {
    int32_t size = student_age_list.size();
    for(int32_t i = 0; i < size; ++i)
        std::cout << "Name: " << student_name_lsit[i] << ", Age: " << student_age_list[i] << "\n";
    std::cout << std::endl;
}

int32_t main(int32_t argc, char *argv[]) {
    std::vector<int32_t> student_age_list { 23, 56, 34, 77, 23, 66, 54, 34 };
    std::vector<std::string> student_name_list { "abc", "sjdg", "gdagd", "twue", "sgfdah", "tywet", "mbmdas", "uyqwteu" };
    
    print(student_age_list, student_name_list);
    
    std::sort(student_age_list.begin(), student_age_list.end(), [](const int32_t& a, const int32_t& b) { return a > b; });
    
    std::cout << "\nAfter sort\n\n";
    print(student_age_list, student_name_list);
    
    return EXIT_SUCCESS;
}

Answer 1

鉴于您显示的代码，根本无法将年龄数据与姓名数据相关联，因此排序一个向量将与另一个向量不同步。

您应该改用 1 个向量。创建一个struct/class 来保存每个学生的数据，然后为该数据使用 1 个向量。例如：

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

struct StudentInfo
{
    std::string name;
    int32_t age;
};

void print(const std::vector<StudentInfo>& student_list) {
    for(const auto &student : student_list)
        std::cout << "Name: " << student.name << ", Age: " << student.age << "\n";
    std::cout << std::endl;
}

int main(int argc, char *argv[]) {
    std::vector<StudentInfo> student_list { {“abc”,23}, {“sjdg”,56}, {“gdagd”,34}, {“twue”,77}, {“sgfdah”,23}, {“tywet”,66}, {“mbmdas”,54}, {“uyqwteu”,34} };
    
    print(student_list);
    
    std::sort(student_list.begin(), student_list.end(), [](const StudentInfo& a, const StudentInfo& b) { return a.age > b.age; });
    
    std::cout << "\nAfter sort\n\n";
    print(student_list);
    
    return EXIT_SUCCESS;
}

Live Demo

如果这不是您的选择，无论出于何种原因，您都必须以某种方式将 2 个矢量数据链接在一起。例如，您可以使用第 3 个向量将索引保存到其他 2 个向量中，然后对索引进行排序，例如：

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

void print(const std::vector<int32_t>& student_age_list, const std::vector<std::string>& student_name_list, const std::vector<size_t>& student_index_list) {
    for(size_t index : student_index_list)
        std::cout << "Name: " << student_name_list[index] << ", Age: " << student_age_list[index] << "\n";
    std::cout << std::endl;
}

int main(int argc, char *argv[]) {
    std::vector<int32_t> student_age_list { 23, 56, 34, 77, 23, 66, 54, 34 };
    std::vector<std::string> student_name_list { "abc", "sjdg", "gdagd", "twue", "sgfdah", "tywet", "mbmdas", "uyqwteu" };
    std::vector<size_t> student_index_list { 0, 1, 2, 3, 4, 5, 6, 7 };
    
    print(student_age_list, student_name_list, student_index_list);
    
    std::sort(student_index_list.begin(), student_index_list.end(), [&](const size_t& a, const size_t& b) { return student_age_list[a] > student_age_list[b]; });
    
    std::cout << "\nAfter sort\n\n";
    print(student_age_list, student_name_list, student_index_list);
    
    return EXIT_SUCCESS;
}

Live Demo