学生信息管理系统
仅供参考，请不要直接用于实际用途
缺陷：对输入变量的管理存在漏洞
#include <iostream>
#include <string>
using namespace std;
const int N = 20;
// 定义普通函数
void Display()
{
cout << "\n************0.退 出*************" << endl;
cout << "************1.录入信息*************" << endl;
cout << "************2.查询信息*************" << endl;
cout << "************3.浏览信息*************" << endl;
}
// 定义类
class Student
{
protected:
string name;
int number;
char sex;
int age;
public:
bool operator==(string p);
virtual void input() = 0;
virtual void output();
};
class Undergraduate : public Student
{
private:
string speciality;
public:
virtual void input();
virtual void output();
};
class Pupil : public Student
{
private:
string school;
int start_year;
public:
virtual void input();
virtual void output();
};
class Interface
{
protected:
public:
Undergraduate dut[N];
Pupil pup[N];
int numU, numP;
public:
Interface();
void Browse(int c);
void Run(int c);
void Input(int c);
bool Search(int c);
};
// 成员函数定义
void Student::output()
{
cout << "Name " << '\t';
cout << "Number " << '\t';
cout << "Sex " << '\t';
cout << "Age " << '\t';
}
bool Student::operator==(string p)
{
return (name == p);
}
void Undergraduate::input()
{
cout << "Enter name: ";
cin >> name;
cout << "Enter number: ";
cin >> number;
cout << "Enter sex: ";
cin >> sex;
cout << "Enter age: ";
cin >> age;
cout << "Enter speciality: ";
cin >> speciality;
}
void Undergraduate::output()
{
Student::output();
cout << "Speciality " << '\n';
}
void Pupil::input()
{
cout << "Enter name: ";
cin >> name;
cout << "Enter number: ";
cin >> number;
cout << "Enter sex: ";
cin >> sex;
cout << "Enter age: ";
cin >> age;
cout << "Enter school: ";
cin >> school;
cout << "Enter start year: ";
cin >> start_year;
}
void Pupil::output()
{
Student::output();
cout << "School " << '\t';
cout << "Start year " << '\n';
}
Interface::Interface()
{
numU = 0;
numP = 0;
}
void Interface::Input(int c)
{
Student *p;
switch (c)
{
case 1:
if (numU == N)
{
cout << "The number of undergraduates is full." << endl;
return;
}
p = &dut[numU];
p->input();
numU++;
break;
case 2:
if (numP == N)
{
cout << "The number of pupils is full." << endl;
return;
}
p = &pup[numP];
p->input();
numP++;
}
}
void Interface::Browse(int c)
{
Student *p;
int num;
if (c == 1)
num = numU;
if (c == 2)
num = numP;
cout << "\n你要浏览的数据\n";
if (num == 0)
{
cout << "没有数据。" << endl;
return;
}
switch (c)
{
case 1:
cout << "Name" << '\t' << "Number" << '\t' << "Sex" << '\t' << "Age" << '\t' << "Speciality" << endl;
for (int i = 0; i < numU; i++)
{
p = &dut[i];
p->output();
}
break;
case 2:
cout << "Name" << '\t' << "Number" << '\t' << "Sex" << '\t' << "Age" << '\t' << "School" << '\t' << "Start year" << endl;
for (int i = 0; i < numP; i++)
{
p = &pup[i];
p->output();
}
break;
}
}
bool Interface::Search(int c)
{
string name;
Student *p;
int num, i;
if (c == 1)
num = numU;
if (c == 2)
num = numP;
cout << "请输入要查询的姓名：";
cin >> name;
switch (c)
{
case 1:
for (i = 0; i < num; i++)
{
p = &dut[i];
if (*p == name)
break;
}
break;
case 2:
for (i = 0; i < num; i++)
{
p = &pup[i];
if (*p == name)
break;
}
if (i == num)
{
cout << "没有找到该学生。" << endl;
return false;
}
else
p->output();
return true;
}
}
void Interface::Run(int c)
{
int choice;
do
{
Display();
cout << "请输入你的选择：";
cin >> choice;
switch (choice)
{
case 1:
Input(c);
break;
case 2:
Search(c);
break;
case 3:
Browse(c);
break;
case 0:
break;
default:
cout << "Error input." << endl;
break;
}
} while (choice);
}
int main()
{
Interface interface;
cout << "大学生信息管理 >>> " << endl;
interface.Run(1);
cout << "小学生信息管理 >>> " << endl;
interface.Run(2);
return 0;
}多态性编程
#include <iostream>
using namespace std;
const double PI = 3.1415;
class shape
{
public:
virtual double volume() = 0;
};
class cylinder : public shape
{
private:
double r, h;
public:
cylinder(double r, double h) : r(r), h(h) {}
double volume()
{
return PI * r * r * h;
}
};
class sphere : public shape
{
private:
double r;
public:
sphere(double r) : r(r) {}
double volume()
{
return 4.0 / 3.0 * PI * r * r * r;
}
};
int main()
{
shape *p;
double r, h;
cin >> r >> h;
cylinder cy(r, h);
sphere sp(r);
p = &cy;
cout << p->volume() << endl;
p = &sp;
cout << p->volume() << endl;
return 0;
}
运算符重载编程
#include<iostream>
using namespace std;
class Matrix
{
private:
int row,col;
int *m;
public:
Matrix(int r,int c):row(r),col(c)
{
m = new int[c*r];
for (int i=0;i<row;i++)
{
for (int j=0;j<col;j++)
cin>>m[i*col+j];
}
}
Matrix()
{
m = new int[9];
}
void disp()
{
for(int i=0;i<row;i++)
{
for(int j=0;j<col;j++)
cout<<m[i*col+j]<<'\t';
cout<<endl;
}
}
Matrix operator+(Matrix &O)
{
if (col!=O.col || row!=O.row)
{
cout<<"program terminated!"<<endl;
exit(0);
}
Matrix temp;
temp.col=col;
temp.row=row;
for(int i=0;i<row;i++)
for(int j=0;j<col;j++)
temp.m[i*col+j] = m[i*col+j] + O.m[i*col+j];
return temp;
}
Matrix operator=(Matrix D)
{
col=D.col;
row=D.row;
for (int i = 0; i <row; i++)
{
for (int j = 0; j <col; j++)
m[i*col+j] = D.m[i*col+j];
}
return *this;
}
};
int main()
{
int row_a,col_a,row_b,col_b;
cin>>row_a>>col_a;
Matrix A(row_a,col_a);
cin>>row_b>>col_b;
Matrix B(row_b,col_b),C;
C = A + B;
C.disp();
cout<<endl;
A = B;
A.disp();
return 0;
}