c++ - 鸟类调查项目在代码中遇到问题。如何像数据库系统一样存储数据

Question

如何将我的输入存储在以下类别中，即水、家禽等。当我提供有关水鸟的信息时，我会提供有关家禽的信息。但是第二个信息会覆盖第一个信息。有没有办法存储数据分类明智？

/* declaring header files */
#include<iostream>
#include<conio.h>
#include<stdio.h>
#include <fstream>
#include <bits/stdc++.h>
#include <string>

using namespace std;
class Bird{

    private:
        char name[50],colour[50],nature[50],location[50];
        float living_duration;

    public:
        int code;
        int set_info(){
            char name='\0';
            char colour='\0';
            char nature='\0';
            char location='\0';
            float living_duration=0.0;
        }
        int get_info(){
            cout<<"\nEnter bird's name: ";
            cin>>name;
            cout<<"Colour: ";
            cin>>colour;
            cout<<"Nature: ";
            cin>>nature;
            cout<<"Location: ";
            cin>>location;
            cout<<"Living Duration: ";
            cin>>living_duration;
            cout<<"Bird's code: ";
            cin>>code;
            }
        int display_info(){
            cout<<"\nBird's name: "<<name;
            cout<<"\nColour     : "<<colour;
            cout<<"\nNature     : "<<nature;
            cout<<"\nlocation     : "<<location;
            cout<<"\nLiving Duration  : "<<living_duration<<" year";
            cout<<"\nCode       : "<<code;
        }
    }obj[100];

int main(){
    int i,j,k,n,m;
    do{
           cout<<"\n\nWhat do you want to do\n1.Input bird's information"
               <<"\n2.Display\n3.Search\n4.Exit."
               <<"\n\nChoose appropriate number: ";
           cin>>n;

           switch(n){
              case 1://bird information
                 cout<<"Please Select Birds Category"<<endl;
                 cout<<"------------------"<<endl;
                 cout<<"1)Water\n2)Domestic\n3)prey\n4)treebased\n5)flightless\n6)migratory\n"<<endl;
                 cin>>m;
                    switch(m){
                    case 1:
                        cout<<"Enter the number of bird how many to input: ";
                        cin>>j;
                        for(i=1;i<=j;i++){
                        cout<<"\nInformation of Bird "<<i<<".\n";
                        obj[i].get_info();
                        }
                        break;
                    case 2:
                        break;
                    case 3:
                        break;
                    case 4:
                        break;
                    case 5:
                        break;
                    case 6:
                        break;
                    default:
                        cout<<"Wrong choice!!\nPlease enter correct number.";
                        break;
                    }


               case 2://display
                  for(i=1;i<=j;i++)
                 {
                  cout<<"\nBird no "<<i<<".\n";
                  obj[i].display_info();
                 cout<<"\n";
                 }
                 break;

               case 3://search
                 cout<<"\nEnter the bird code: ";
                 cin>>k;

                 for(i=1;i<=j;i++)
                  {
                 if(k==obj[i].code)
                    {
                     cout<<"\nBird no "<<i<<".\n";
                     obj[i].display_info();
                     break;
                    }
                   }
                 if(k!=obj[i].code)
                   cout<<"Wrong code input...\n";
                  break;

               case 4://exit
                  break;

               default:
                  cout<<"Wrong choice!!\nPlease enter correct number.";
                  break;
             }

         }while(n!=4);
  }

Answer 1

您需要将您的概念分为鸟类数据 和数据的容器。

在关系数据库中，您会有表。让表的列由结构的数据成员表示。表的一条记录(行)将是记录结构的一个实例:

class Bird
{
public:
  std::string name;
  std::string colour;
  std::string nature;
  std::string location;
  float       living_duration;
};

对于容器或表，您可以使用 std::vector :
std::vector<Bird> bird_table;

许多关系数据库还包含索引表以加快搜索速度。索引表将包含对、键(或列值)和 std::vector 中的索引。 . C++ 语言有一个方便的容器，称为 std::map :

std::map<string, unsigned int> name_index;

string参数表示键或列类型。
unsigned int参数表示数据库中的索引(也称为外键)。

要按名称检索 Bird 记录，您首先访问索引表，然后访问 vector :

   unsigned int database_index = name_index["crow"];
   Bird  crow = database[index];