c++学生管理系统

【核心代码】

#include "stdafx.h"
#include<iostream>
#include<iomanip>
#include<fstream>       
#include<sstream>

using namespace std;
class student
{
int num;
char name[20];
char class1[20];
double chinese;
double math;
double english;
double sum;

public:
double ad(){ return sum = chinese english math; }
void set()
{
cout << "\t学生学号：";
cin >> num;
cout << "\t学生姓名：";
cin >> name;
cout << "\t学生班级：";
cin >> class1;
cout << "\t语文成绩：";
cin >> chinese;
cout << "\t数学成绩：";
cin >> math;
cout << "\t英语成绩：";
cin >> english;
}
friend void input();
friend void show();
friend void find();
friend void modify();
friend void add();
friend void order();
friend void del();
};

student s[100];
int n = 0;

int main()
{
int select;
while (1)
{
system("cls");
cout << "\t ******************欢迎使用******************"<<endl;
cout << "\t **************学生成绩管理系统**************\n";
cout << "\t *------------------------------------------*\n";
cout << "\t *         1——录入学生信息                *\n";
cout << "\t *         2——显示学生信息                *\n";
cout << "\t *         3——查询学生信息                *\n";
cout << "\t *         4——修改学生信息                *\n";
cout << "\t *         5——添加学生信息                *\n";
cout << "\t *         6——排序学生信息                *\n";
cout << "\t *         7——删除学生信息                *\n";
cout << "\t *         0——退出                        *\n";
cout << "\t *------------------------------------------*\n";
cout << "\t 你要输入的编号是（0--7）:";
cin >> select;
switch (select)
{
case 1:
input();
system("pause");
break;
case 2:
show();
system("pause");
break;
case 3:
find();
system("pause");
break;
case 4:
modify();
system("pause");
break;
case 0:
break;
default:
cout<<"输入错误！！请重新输入：";
system("pause");
break;
}
}
}

void input()
{

char sel;
do
{
n ;
cout << "\t请录入第" << n << "个学生信息"<<endl;
s[n].set();
cout << "是否继续录入学生信息（y/n）：";
cin >> sel;
}while(sel == 'y'||sel == 'Y');

}

void show()
{
cout << left << 
setw(10) << "学生学号" <<
setw(10) << "学生姓名" <<
setw(10) << "学生班级" <<
setw(10) << "语文成绩" <<
setw(10) << "数学成绩" <<
setw(10) << "英语成绩" << endl;
for (int i = 1; i <= n; i )
{
cout << left <<
setw(10) <<s[i].num <<
setw(10) << s[i].name <<
setw(10) << s[i].class1 <<
setw(10) << s[i].chinese <<
setw(10) << s[i].math <<
setw(10) << s[i].english << endl;
}
}

void find()
{
char sel,c[20];
int a,b;
cout << "查找方式:" << endl;
cout << "1.按学号查找" << endl;
cout << "2.按姓名查找" << endl;
cout << "请输入查找方式：";
cin >> a;

switch (a)
{
case 1:
{
do
{
cout << "请输入要查找学生的学号：";
cin >> b;
for (int i = 1; i <= n; i )
if (s[i].num == b)
{
cout << left <<
setw(10) << "学生学号" <<
setw(10) << "学生姓名" <<
setw(10) << "学生班级" <<
setw(10) << "语文成绩" <<
setw(10) << "数学成绩" <<
setw(10) << "英语成绩" << endl;
cout << left <<
setw(10) << s[i].num <<
setw(10) << s[i].name <<
setw(10) << s[i].class1 <<
setw(10) << s[i].chinese <<
setw(10) << s[i].math <<
setw(10) << s[i].english << endl;
break;
}
else if (s[i].num, b != 0 && i == n)
{
cout << "您输入的数据有误！！请查证后重新输入"<<endl;
break;
}
cout << "是否继续查找学生（y/n）：";
cin >> sel;
} while (sel == 'y' || sel == 'Y');
break;
}
case 2:
{
do
{
cout << "请输入要查找学生的姓名：";
cin >> c;
for (int i = 1; i <= n; i )
if (strcmp(s[i].name, c) == 0)
{
cout << left <<
setw(10) << "学生学号" <<
setw(10) << "学生姓名" <<
setw(10) << "学生班级" <<
setw(10) << "语文成绩" <<
setw(10) << "数学成绩" <<
setw(10) << "英语成绩" << endl;
cout << left <<
setw(10) << s[i].num <<
setw(10) << s[i].name <<
setw(10) << s[i].class1 <<
setw(10) << s[i].chinese <<
setw(10) << s[i].math <<
setw(10) << s[i].english << endl;
break;
}
else if (strcmp(s[i].name, c) != 0 && i == n)
{
cout << "您输入的数据有误！！请重新输入：";
break;
}
cout << "是否继续查找学生（y/n）：";
cin >> sel;
} while (sel == 'y' || sel == 'Y');
break;
}
}
}

void modify()
{
char sel;
char d[20];
int i;
do
{
cout << "请输入要修改学生的姓名：";
cin >> d;
int e;
for (i = 1; i <= n; i )
{
if (strcmp(s[i].name, d) == 0)
{
cout << "要修改的学生信息为：" << endl;
cout << "1.学生学号:" << s[i].num << ", " <<
"2.学生姓名:" << s[i].name << ", " <<
"3.学生班级:" << s[i].class1 << ", " <<
"4.学生语文:" << s[i].chinese << ", " <<
"5.学生数学:" << s[i].math << ", " <<
"6.学生英语:" << s[i].english << endl;
cout << "请输入要修改的项编号：";
cin >> e;
switch (e)
{
case 1:
cout << "学生新的学号为：";
cin >> s[i].num;
break;
case 2:
cout << "学生新的姓名为：";
cin >> s[i].name;
break;
case 3:
cout << "学生新的班级为：";
cin >> s[i].class1;
break;
case 4:
cout << "学生新的语文成绩为：";
cin >> s[i].chinese;
break;
case 5:
cout << "学生新的数学成绩为：";
cin >> s[i].math;
break;
case 6:
cout << "学生新的英语成绩为：";
cin >> s[i].english;
break;
default:
break;
}
}
}
cout << "是否继续修改学生信息（y/n）：";
cin >> sel;
}while(sel == 'y' || sel == 'Y');
}