离小学期结束还有三天，今天完成了小学期的第二个项目，用标准函数库完成学生成绩管理系统。明天继续研究链表。
代码：
#include<iostream>
#include<fstream>
#include<string>
#include<vector>
using namespace std;
struct StudentInfo
{
int itsnumber;
string itsname;
double itsMath;
double itsChinese;
double itsEnglish;
double itsSum;
double itsAverage;
};
class StudentManage
{
private:
vector<StudentInfo>stu;
public:
void Create(); //创建文件
void Import();//导入
void show();//显示
void setdata(); //输入n名学生的信息
void DeleteData(); //删除
void alterData(); //修改
void queryData(); //查询
void Summary(); //汇总
void sortData(); //排序
void exportData(); //导出
void addDate(); //插入数据
};
void StudentManage::Create() //创建文件
{
string filename;
cout << "请输入文件名" << endl;
cin >> filename;
ofstream outfile;
outfile.open(filename.c_str(), ios::out); //打开输入文件，达到的创建的作用
if (!outfile) //如果未能打开则报错
{
cerr << "打开" << filename << "失败！！" << endl;
exit(0);
}
else
{
cout << "创建成功！！" << endl;
}
outfile.close();
}
void StudentManage::Import() //导入
{
int i = 0, j = 0, h = 0;
string filename;
cout << "请输入文件名：" << endl;
cin >> filename;
ifstream infile(filename.c_str()); //打开输入文件
if (!infile) //如果未能打开则报错
{
cerr << "打开" << filename << "失败！！" << endl;
//exit(0); //少了该句则可以返回菜单，继续操作
}
else
{
cout << "打开成功！！" << endl;
}
while (infile)
{
char c = infile.get();
if (infile) cout << c;
}
cout << "导入成功！！" << endl;
infile.close();
}
void StudentManage::show() //显示
{
for(vector<StudentInfo>::iterator it=stu.begin();it<stu.end();it++)
cout << (*it).itsname << " " << (*it).itsnumber << " " << (*it).itsChinese << " " << (*it).itsMath << " " << (*it).itsEnglish << " " << (*it).itsSum << " " << (*it).itsAverage << endl;
}
void StudentManage::setdata() //输入n名学生的信息
{
StudentInfo s;
int n;
cout << "请输入学生总数：";
cin >> n;
for (int i = 0; i < n; i++)
{
cin >> s.itsname >> s.itsnumber >> s.itsChinese >>s.itsMath >> s.itsEnglish;
stu.push_back(s); //在模板尾部插入数据
}
}
void StudentManage::DeleteData() //删除
{
int a;
int flag = 0; //用于判断是否找到并删除改学生
cout << "请输入所要删除的学生的学号：";
cin >> a;
for (int i = 0; i < stu.size(); i++)
{
if (stu[i].itsnumber == a)
{
flag = 1;
stu.erase(stu.begin() + i); //删除该位置的数据
cout << "删除成功" << endl;
break;
}
}
if (flag == 0) cout << "输入学号有误，请重新输入" << endl;
}
void StudentManage::alterData()//修改
{
int a;
int flag = 0, f = 1; //用于判断是否找到并修改改学生
cout << "请输入所要修改的学生的学号：";
cin >> a;
for (int i = 0; i < stu.size(); i++)
{
if (stu[i].itsnumber == a)
{
flag = 1;
while (f == 1)
{
int x;
long a;
double b, c, d;
string e;
cout << "---修改操作菜单---" << endl;
cout << "1.学号" << endl;
cout << "2.姓名" << endl;
cout << "3.语文成绩" << endl;
cout << "4.数学成绩" << endl;
cout << "5.英语成绩" << endl;
cout << "6.退出返回" << endl;
cout << "请选择：";
cin >> x;
switch (x)
{
case 1:
cout << "请输入修改后的学号：" << endl;
cin >> a;
stu[i].itsnumber = a;
break;
case 2:
cout << "请输入修改后的姓名：" << endl;
cin >> e;
stu[i].itsname = e;
break;
case 3:
cout << "请输入修改后的语文成绩：" << endl;
cin >> b;
stu[i].itsChinese = b;
break;
case 4:
cout << "请输入修改后的数学成绩：" << endl;
cin >> c;
stu[i].itsMath = c;
break;
case 5:
cout << "请输入修改后的英语成绩：" << endl;
cin >> d;
stu[i].itsEnglish = d;
break;
case 6:
f = 0;
break;
default:cout << "选择错误，请重新选择！！" << endl;
}
}
}
}
if (flag == 0) cout << "输入学号有误，请重新输入!" << endl;
else
{
cout << "修改成功!!" << endl;
cout << "重新汇总中......." << endl;
Summary();//对修改的成绩重新汇总
}
}
void StudentManage::queryData() //查询
{
int a;
int flag = 0; //用于判断是否找到该学生
cout << "请输入所要查询的学生的学号：";
cin >> a;
for (int i = 0; i < stu.size(); i++)
{
if (stu[i].itsnumber == a)
{
flag = 1;
cout << "姓名：" << stu[i].itsname << endl;
cout << "学号：" << stu[i].itsnumber << endl;
cout << "语文：" << stu[i].itsChinese << endl;
cout << "数学：" << stu[i].itsMath << endl;
cout << "英语：" << stu[i].itsEnglish << endl;
cout << "总分：" << stu[i].itsSum << endl;
cout << "平均分：" << stu[i].itsAverage << endl;
break;
}
}
if (flag == 0) cout << "输入学号有误，请重新输入" << endl;
}
void StudentManage::Summary() //汇总
{
for (int i = 0; i < stu.size(); i++)
{
stu[i].itsSum = stu[i].itsChinese + stu[i].itsMath + stu[i].itsEnglish;
stu[i].itsAverage = stu[i].itsSum / 3.0;
}
cout << "汇总完成！！！" << endl;
}
void StudentManage::sortData() //排序
{
int x;
StudentInfo temp;
cout << "----排序菜单----" << endl;
cout << "1.按学号升序排序" << endl;
cout << "2.按学号降序排序" << endl;
cout << "3.按总分升序排序" << endl;
cout << "4.按总分降序排序" << endl;
cout << "请选择：";
cin >> x;
switch (x)
{
//按学号升序排序并输出
case 1:
for (int j = 0; j < stu.size() - 1; j++)
for (int i = 0; i < stu.size() - 1 - j; i++)
if (stu[i].itsnumber > stu[i + 1].itsnumber)
{
temp = stu[i];
stu[i] = stu[i + 1];
stu[i + 1] = temp;
}
cout << "排序结果为" << endl;
show();
break;
//按学号降序排序并输出
case 2:
for (int j = 0; j < stu.size() - 1; j++)
for (int i = 0; i < stu.size() - 1 - j; i++)
if (stu[i].itsnumber < stu[i + 1].itsnumber)
{
temp = stu[i];
stu[i] = stu[i + 1];
stu[i + 1] = temp;
}
cout << "排序结果为" << endl;
show();
break;
//按总分升序排序并输出
case 3:
for (int j = 0; j < stu.size() - 1; j++)
for (int i = 0; i < stu.size() - 1 - j; i++)
if (stu[i].itsSum > stu[i + 1].itsSum)
{
temp = stu[i];
stu[i] = stu[i + 1];
stu[i + 1] = temp;
}
cout << "排序结果为" << endl;
show();
break;
//按总分降序排序并输出
case 4:
for (int j = 0; j < stu.size() - 1; j++)
for (int i = 0; i < stu.size() - 1 - j; i++)
if (stu[i].itsSum < stu[i + 1].itsSum)
{
temp = stu[i];
stu[i] = stu[i + 1];
stu[i + 1] = temp;
}
cout << "排序结果为" << endl;
show();
break;
}
}
void StudentManage::exportData() //导出
{
int i = 0;
string filename;
cout << "请输入文件名：" << endl;
cin >> filename;
ofstream outfile(filename.c_str()); //打开输入文件
if (!outfile) //如果未能打开则报错
{
cerr << "打开" << filename << "失败！！" << endl;
//exit(0); //少了该句则可以返回菜单，继续操作
}
else
{
cout << "打开成功！！" << endl;
}
for (i = 0; i < stu.size(); i++)
{
outfile << stu[i].itsname << " " << stu[i].itsnumber << " " << stu[i].itsChinese << " " << stu[i].itsMath << " " << stu[i].itsEnglish << " " << stu[i].itsSum << " " << stu[i].itsAverage << endl;
}
cout << "导出到文件成功！！" << endl;
}
void StudentManage:: addDate() //插入数据
{
int a;
int b, flag = 0;
cout << "请输入想要插入到的位置（某个学号前)" << endl;
cin >> a;
cout << "请输入添加的学生数目：";
cin >> b;
vector<StudentInfo>stu1;
StudentInfo temp;
for (int i = 0; i < stu.size(); i++)
{
if (stu[i].itsnumber == a)
{
flag = 1; //找到该学号的标志
for (int j = 0; j < b; j++)
{
cin >> temp.itsname >> temp.itsnumber >> temp.itsChinese >> temp.itsMath >> temp.itsEnglish;
stu1.push_back(temp);
}
stu.insert(stu.begin() + b - 1, stu1.begin(), stu1.end());
break;
}
}
if (flag == 0) cout << "学号输入错误，请重新输入！！" << endl;
else
{
cout << "插入成功" << endl;
cout << "重新汇总中......." << endl;
Summary();
}
}
void menu() //菜单
{
cout << "-----学生成绩管理-----" << endl;
cout << "1 创建" << endl;
cout << "2 导入" << endl;
cout << "3 显示" << endl;
cout << "4 输入" << endl;
cout << "5 删除" << endl;
cout << "6 修改" << endl;
cout << "7 查询" << endl;
cout << "8 汇总" << endl;
cout << "9 排序" << endl;
cout << "10 导出" << endl;
cout << "11 插入" << endl;
cout << "12 退出" << endl;
cout << "请选择：" << endl;
}
void main()
{
int i;
StudentManage S;
do
{
menu();
cin >> i;
switch (i)
{
case 1:cout << "-----创建-----" << endl;
S.Create();
break;
case 2:
cout << "-----导入-----" << endl;
S.Import();
break;
case 3:
cout << "-----显示-----" << endl;
S.show();
break;
case 4:
cout << "-----输入-----" << endl;
S.setdata();
break;
case 5:
cout << "-----删除-----" << endl;
S.DeleteData();
break;
case 6:
cout << "-----修改-----" << endl;
S.alterData();
break;
case 7:
cout << "-----查询-----" << endl;
S.queryData();
break;
case 8:
cout << "-----汇总-----" << endl;
S.Summary();
break;
case 9:
cout << "-----排序-----" << endl;
S.sortData();
break;
case 10:
cout << "-----导出-----" << endl;
S.exportData();
break;
case 11:
cout << "-----插入-----" << endl;
S.addDate();
break;
case 12:
cout << "-----退出-----" << endl;
exit(0);
break;
default:cout << "选择错误，请重新选择！！" << endl;
}
} while (i != 0);
}