整体思路：
实现代码
#include <iostream>#include<fstream>#include<string>#define line for (int n = 0; n <= 100; n++) cout << "-"#define FILENAME "stdu.dat"using namespace std;class student { //学生类public: int Is_Exist(string stuId, int a); int get_student_number(); //获取文件中学生人数 bool File_Is_Empty; //文件是否为空的标识 student *studentArray; //将文件中的内容，以student对象方式储存在studentArray[]数组中 int student_number; //学生人数 string studentId; //学号 string name; //姓名 float score[3];//成绩*3 float Total; // 总分 int Average;//平均分 void sort(int n=1); //排序函数 void delete_stu(); //删除学生 void init(); //初始化内容，将文件中的内容读到studentArray中 void save(); //保存文件 void show();//展示界面 void add_stu(int number = 1); //添加学生 void showInfo(); //展示学生信息 void search();//搜索学生 student() //默认构造函数，判断文件是否为空，设置File_Is_Empty值 { ifstream ifs; ifs.open(FILENAME, ios::in); if (!ifs.is_open()) { this->student_number = 0; this->studentArray = NULL; this->studentId = "0"; this->name = "0"; this->score[0] = 0; this->Average = 0; this->Total = 0; this->File_Is_Empty = true; ifs.close(); return; } char c; ifs >> c; if (ifs.eof()) { //文件空 this->student_number = 0; this->studentArray = NULL; this->studentId = "0"; this->name = "0"; this->score[0] = 0; this->Average = 0; this->Total = 0; this->File_Is_Empty = true; ifs.close(); return; } int num = this->get_student_number(); //获取文件中学生数量 this->student_number = num; //cout << "现在学生人数为:" << num << endl;; //system("pause"); }; ~student() //析构函数 { delete[]this->studentArray; this->studentArray = NULL; //防止指针变为野指针 } student(string stuId,string stuName, float stuScore[3]) //带参数的构造函数 { this->studentId = stuId; this->name = stuName; for (int i = 0; i < 3; i++) this->score[i] = stuScore[i]; this->Average = (stuScore[0] + stuScore[1] + stuScore[2]) / 3; this->Total = stuScore[0] + stuScore[1] + stuScore[2]; };};void student::sort(int n) //排序，当n=1的时候为按学号排序，n=2为按总成绩排序{ int num1; //学号在设计的时候是string类型，用int类型排序需要atoi，用num接收转换过的值 int num2; // student a; //用于交换对象数组的中间变量 if (this->File_Is_Empty) //判断文件是否为空 { cout << "数据文件不存在或者为空\n"; system("pause"); } else { cout << "3.学生信息排序\n"; if (n == 1) { cout << "将学生信息按学号顺序排序\n"; for (int i = 0; i < this->student_number - 1; i++)//冒泡排序 { for (int t = 0; t < this->student_number - 1 - i; t++) { num1 = atoi(this->studentArray[t].studentId.c_str()); //将string类型变量变为int类型 num2 = atoi(this->studentArray[t + 1].studentId.c_str()); if (num1 > num2) a = this->studentArray[t + 1], this->studentArray[t + 1] = this->studentArray[t], this->studentArray[t] = a; } } } if (n == 2) { cout << "将学生信息按总成绩顺序排序\n"; for (int i = 0; i < this->student_number - 1; i++)//冒泡排序 { for (int t = 0; t < this->student_number - 1 - i; t++) { if (this->studentArray[t].Total > this->studentArray[t + 1].Total) a = this->studentArray[t + 1], this->studentArray[t + 1] = this->studentArray[t], this->studentArray[t] = a; } } } }}void student::search() //查找学生成绩{ string id; int ret; //studentArray[]的下标,在Is_Exist()中 int a = 1; //判断根据学号查找还是姓名查找 cout << "4.查找学生成绩\n" << "1.按照学号查找\t2.根据姓名查找\n输入你的选项>"; cin >> a; if (a == 1) { cout << "请输入学号:", cin >> id; ret = this->Is_Exist(id, 1); } else if (a == 2) { cout << "请输入姓名:", cin >> id; ret = this->Is_Exist(id, 2); } else { ret = this->Is_Exist(id, 1); } if (ret == -1) { system("cls"); cout << "学生不存在" << endl; } else { cout << "查找成功，下面为该学生信息\n" << endl; cout << "学号:" << this->studentArray[ret].studentId << " 姓名:" << this->studentArray[ret].name << endl << "各门成绩:语文:" << this->studentArray[ret].score[0] << " 数学:" << this->studentArray[ret].score[0] << " 英语:" << this->studentArray[ret].score[2] << " 平均成绩:" << this->studentArray[ret].Average << " 总成绩:" << this->studentArray[ret].Total << endl; } system("pause"); }int student::Is_Exist(string stuId,int a){ //a=1 则使用学生学号查找 //a=2 则使用学生姓名查找 if (File_Is_Empty) //判断文件是否不存在或者为空，如果为空则返回-2 { cout << "数据文件不存在或者为空\n"; system("pause"); return -2; } for (int i = 0; i < this->student_number; i++) { if ((a==1)&&(this->studentArray[i].studentId == stuId)) //根据学号查找 { return i; } if ((a == 2) && (this->studentArray[i].name == stuId)) //根据姓名查找 { return i; } } return -1; //如果没找到返回-1}void student::delete_stu() //删除学生{ int ret; //接收 Is_Exist的返回值，返回值是此学生在studentArray[]里的下标 string id; //可以用来接收学号或者姓名 int a = 1; //判断是按照学生学号寻找还是根据学生姓名寻找 cout << "5.删除学生成绩\n" << "1.按照学号删除\t2.根据姓名删除\n输入你的选项>"; cin >> a; if (a == 1) //按照学生学号查找 { cout << "请输入学号:", cin >> id; ret = this->Is_Exist(id, 1); } else if(a==2)//按照学生姓名 { cout << "请输入姓名:", cin >> id; ret = this->Is_Exist(id, 2); } else //默认按照学生学号进行查找 { cout << "请输入学号:", cin >> id; ret = this->Is_Exist(id, 1); } if (ret == -1) //返回值为-1则学生不存在 { system("cls"); cout << "学生不存在"<<endl; } else if(ret == -2) //返回值为-2文件不存在或为空，直接退出函数 { return; } else //如果学生信息存在，并且ret是studentArray[]中的下标 {//输出要删除的学生信息 cout << "该学生的信息将被删除"<<endl; cout << "学号:" << this->studentArray[ret].studentId << " 姓名:" << this->studentArray[ret].name << endl << "各门成绩:语文:" << this->studentArray[ret].score[0] << " 数学:" << this->studentArray[ret].score[0] << " 英语:" << this->studentArray[ret].score[2] << " 平均成绩:" << this->studentArray[ret].Average << " 总成绩:" << this->studentArray[ret].Total << endl; for (int i = ret; i < this->student_number - 1; i++) { this->studentArray[i] = this->studentArray[i + 1]; } this->student_number--; this->save(); } system("pause");}void student::init(){ string name; //用来储存读取到的姓名 string student_id;//用来储存读取到的学号 int i = 0; //标识符，用来把实例化的类储存到对应的对象数组 float score[3]; //用来储存读取到的成绩 float total; //用来储存读取到的成总分 int average; //用来储存读取到的平均分 ifstream inf; //实例化一个文件对象 this->studentArray = new student[this->student_number]; //根据读取到的学生数量开辟空间，学生数量 inf.open(FILENAME, ios::in); while (inf >> student_id && inf >> name && inf >> score[0]&& inf >> score[1] && inf >> score[2] && inf >> average && inf >> total) { //格式化读取文件,从文件读到变量 student stu(student_id, name, score); //使用读到的值实例化student对象 this->studentArray[i] = stu; //把实例化的对象放到stu1对象的studentArray中 i++; }}int student::get_student_number() //获取文件中学生的数量，在add_stu()函数中加上需要增加的学生数量，为最新需要开辟的空间的大小{ string name; string student_id; int num=0; //每格式化读取一块数据，则加1人数 float score[3]; float total; int average; ifstream inf; inf.open(FILENAME, ios::in); while (inf >> student_id && inf >> name && inf >> score[0] && inf >> score[1] && inf >> score[2] && inf >> average && inf >> total) { num++; } inf.close(); return num; //返回学生数量}void student::save() //将stu1中studentArray中的每个student对象储存到文件中{ ofstream ofs; ofs.open(FILENAME,ios::out); for (int i = 0; i < this->student_number; i++) { ofs << this->studentArray[i].studentId << " " << this->studentArray[i].name << " " << this->studentArray[i].score[0] << " " << this->studentArray[i].score[1] << " " << this->studentArray[i].score[2]<< " " <<this->studentArray[i].Average<<" "<< this->studentArray->Total<<" "; }}void student::showInfo() //显示学生信息{ if (this->File_Is_Empty) //构造函数里的文件标识符，判断文件是否存在或者为空，每实例化一个对象都检查一遍 { system("cls"); cout << "文件不存在或内容为空,请先输入数据\n"; } else { //文件不为空则输出stu1中studentArray中储存的内容 for (int i=0;i<this->student_number;i++) { cout << "学号:" << this->studentArray[i].studentId << " 姓名:" << this->studentArray[i].name << endl << "各门成绩:语文:" << this->studentArray[i].score[0] << " 数学:" << this->studentArray[i].score[1] << " 英语:" << this->studentArray[i].score[2] << " 平均成绩:" << this->studentArray[i].Average << " 总成绩:" << this->studentArray[i].Total << endl; line; cout << endl; } } system("pause");}void student::add_stu(int add_number) //添加学生{ //计算需要的新的空间大小 int newsize = this->student_number + add_number; //需要开辟的空间 = 文件中学生的人数+需要添加的数量 //cout << "newxize=" << newsize; student *newspace = new student[newsize]; //开辟内存空间 student *stu3; string name; string studentId; float score[3]; if (this->studentArray!= NULL) //如果studentArray不为空就先将studentArray中的内容先复制到newspace数组中，再在newspace中增加学生信息, //最后再将newspace的内容复制到studentArray中，实现动态数组 { for (int i = 0; i < this->student_number; i++) { newspace[i] = this->studentArray[i]; } } for (int i = 0; i < add_number; i++) //输入学生信息 { cout << "请输入学生姓名:", cin >> name, cout << endl; cout << "请输入学生学号:", cin >> studentId, cout << endl; cout << "请输入学生语文成绩:", cin >> score[0], cout << endl; cout << "请输入学生数学成绩:", cin >> score[1], cout << endl; cout << "请输入学生英语成绩:", cin >> score[2], cout << endl; line; cout << endl; student stu3(studentId, name, score); //将输入的内容实例化成对象 newspace[this->student_number + i] = stu3; //将对象依次储存到newspace中 } delete[] this->studentArray; this->studentArray = newspace; //将newspace赋给studentArray，用来在别的成员函数中访问 this->student_number = newsize; //更新学生人数大小 this->File_Is_Empty = false; // 输入了内容以后，文件不为空 this->save(); //保存到文件中 cout << "添加成功"<<endl; system("pause");}void student::show(){ cout << "1.输入学生成绩" << endl << "2.增加学生成绩" << endl << "3.学生信息排序" << endl << "4.查找学生成绩" << endl << "5.删除学生成绩" << endl << "6.显示学生成绩" << endl << "7.安全退出系统" << endl; line; cout << endl; cout<< "输入你的选择>:";}student stu1; //实例化对象，此时已经得到文件中的学生数量int main(){ int choice=7; stu1.init(); // 将文件里的内容按照格式读入内存，储存到// cout << "stu1里的人数" << stu1.student_number;// system("pause"); while (true) { system("cls"); stu1.show(); cin >> choice; line; cout << endl; if (cin.good() && choice <= 7 && choice >= 1) //判断用户输入是否合法 { switch (choice) { case 1: //添加学生功能，默认参数为1，用来增加学生时直接调用，初始化添加十个学生时传递参数10 stu1.add_stu(10); break; case 2: //增加学生，要求按照学号顺序插入,则在增加学生后调用排序函数，再进行保存 { stu1.add_stu(); stu1.sort(); stu1.save(); } break; case 3: //排序功能 { int n = 1; cout << "1.按照学号排序\t2.按照总成绩排序\n"; cin >> n; stu1.sort(n); stu1.showInfo(); } break; case 4: //搜索功能 stu1.search(); break; case 5: //删除功能 stu1.delete_stu(); break; case 6: //显示学生信息 stu1.showInfo(); break; case 7: //退出程序 return 0; break; default: system("cls"); break; } } else { //归位cin标识符，不至于死循环 cin.clear(); cin.ignore(); cout << "非法数据"<<endl; system("pause"); } }}
界面简陋，加点“ - ”，加点“ * ”，可能会好点，或者干脆用qt写个界面也可以
