Home > Article > Backend Development > Using C++ to implement data management functions
This article mainly talks about adding, deleting, querying and sorting data through C.
Here, I use student data management to give an example:
Requires the following functions:
1. Information entry: enter student performance information (including student number, name, grades of each course, etc.);
2. Information query: enter student No. to query the students' scores in each course and display them.
3. Sorting: Sort by the average score of each course and display it.
4. Information deletion and modification - enter the student number to delete the student's grade information.
Step-by-step implementation:
1. Preliminarily complete the overall design, set up the framework, determine the interface for human-computer dialogue, and determine the number of functions.
2. Create a file, write each student's information into the file and display it on the screen.
3. Complete the above information query (student ID number, name, etc.), sorting, information deletion and modification functions.
#include <iostream> #include <string.h> using namespace std; #define MAX 100 class CStudent {private: char *name; // 姓名 bool sex; // 性别 CDate date; // 出生日期,类对象作数据成员 public: static int num; // 学生人数 CStudent(); void InputData(); friend void Sort(); // 排序 friend void FindName(); // 按姓名查询 friend void Statistic(); // 按性别统计 friend void Display(); // 显示全部信息} stu[MAX]; int CStudent::num=0; //static 初始化 CStudent::CStudent() {} //构造函数// 输入信息 void CStudent::InputData() { int p; char s[41]; cout<<"请输入学生信息(NO."<<num<<"):\n"; cout<<"姓名:"; cin>>s; name=new char[strlen(s)+1]; strcpy(name,s); cout<<"性别(1-男,0-女):"; cin>>p; if (p) sex=true; else sex=false; cin>>date;//操作符重载->istream &operator>>(istream &in,CDate &d) cout<<endl; }// 排序 根据data从小到大排序 void Sort() { int i,j,p,num; char *tn; bool ts; CDate td; num=CStudent::num; for(i=1; i<num; i++) { p=i; for(j=i+1; j<=num; j++) if (stu[j].date<stu[p].date) p=j;//找到当前未排序元素中年龄最小的对象的下标 if (p==i) continue; //下面交换stu[i]和stu[p] tn=stu[i].name; stu[i].name=stu[p].name; stu[p].name=tn; ts=stu[i].sex; stu[i].sex=stu[p].sex; stu[p].sex=ts; td=stu[i].date; stu[i].date=stu[p].date; stu[p].date=td; } }// 按姓名查询 void FindName() { char name[41]; int i,num; cout<<"请输入姓名:"; cin>>name; num=CStudent::num; for(i=1; i<=num; i++) if (strcmp(stu[i].name,name)==0) break; if (i>num) { cout<<"查无此人!"<<endl<<endl; return; } //如果查到了,显示学生信息 cout<<"姓名:"<<stu[i].name<<endl; cout<<"性别:"; if (stu[i].sex) cout<<"男"<<endl; else cout<<"女"<<endl; cout<<"生日:"<<stu[i].date<<endl; cout<<endl; }// 按性别统计 void Statistic() { int i,num,s1,s0; num=CStudent::num; s1=0; s0=0; for(i=1; i<=num; i++) if (stu[i].sex==1)s1++; else s0++; cout<<"男生人数:"<<s1<<endl; cout<<"女生人数:"<<s0<<endl; cout<<endl; }// 显示全部信息 void Display() { int i,num; num=CStudent::num; for(i=1; i<=num; i++) { cout<<stu[i].name<<"\t"; if (stu[i].sex) cout<<"男"; else cout<<"女"; cout<<"\t"<<stu[i].date<<endl; } cout<<endl; } int main1() { char *menu[]= { "","输入信息","排序","按姓名查询","按性别统计","显示全部信息","退出" }; int i,p; bool end; end=false; while(!end) { for(i=1; i<7; i++) cout<<i<<" "<<menu[i]<<endl; cin>>p; switch(p) { case 1: // 输入信息 CStudent::num++; stu[CStudent::num].InputData(); break; case 2: // 排序 Sort(); break; case 3: // 按姓名查询 FindName(); break; case 4: // 按性别统计人数 Statistic(); break; case 5: // 显示全部信息 Display(); break; case 6: // 退出 end=true; break; } } return 0; }
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