都来看看，帮帮忙。
#include <iostream>#include <fstream>
#include <ostream>
#include <string>
using namespace std;
class cstudent
{
private:
int num; //学号
string name; //姓名
char sex; //性别,男为M，女为F
int age; //年龄
float math_score; //数学成绩
float computer_score; //计算机成绩
float English_score; //英语成绩
float average_score; //平均成绩
float all; //总成绩
public:
friend void search_num(); //按学号查找
friend void search_name(); //按姓名查找
friend void search_all_sex(); //按成绩和性别查找
void fun(); //计算总成绩和平均成绩
void input(); //输入学生信息
void output(); //输出学生信息
};
int n; cstudent *a=new cstudent[n]; //定义学生人数为n，并建立n个对象
ofstream outfile;
ifstream infile;
void cstudent::fun()
{
all=math_score+computer_score+English_score;cout<<"总成绩："<<all<<endl;
average_score=all/3;cout<<"平均成绩:"<<average_score<<endl;
}
void cstudent::output()
{
cout<<"学号:"; cout<<num; cout<<endl;
cout<<"姓名:"; cout<<name; cout<<endl;
cout<<"性别:"; cout<<sex; cout<<endl;
cout<<"年龄:"; cout<<age; cout<<endl;
cout<<"数学成绩:"; cout<<math_score; cout<<endl;
cout<<"计算机成绩:"; cout<<computer_score; cout<<endl;
cout<<"英语成绩:"; cout<<English_score; cout<<endl;
cout<<endl;
}
void cstudent::input()
{
cout<<"学号:"; cin>>num; cout<<endl;
cout<<"姓名:"; cin>>name; cout<<endl;
cout<<"性别:"; cin>>sex; cout<<endl;
cout<<"年龄:"; cin>>age; cout<<endl;
cout<<"数学成绩:"; cin>>math_score; cout<<endl;
cout<<"计算机成绩:"; cin>>computer_score; cout<<endl;
cout<<"英语成绩:"; cin>>English_score; cout<<endl;
cout<<endl;
}
void search_num()
{
int number,j=0;
cout<<"请输入学号:";
cin>>number;
while(cin.fail())
{
cout<<"输入错误!"<<endl<<"学号必须是整数!请检查后重试!"<<endl;
cin>>number;
}
ifstream infile("D:\\学生信息.txt",ios::binary);
if (!infile)
{
cerr<<"文件打开失败"<<endl;
exit(1);
}
infile.seekg(0,ios::beg);
for (int i=0;i<2;i++)
{
infile.read((char *)&a[i],sizeof(a[i]));
if (number==a[i].num)
{
j=1;
a[i].output();
}
if (j!=1)
cout<<"对不起，没有该学号的学生!"<<endl;
}
}
void search_name()
{
int j=0;
string s;
cout<<"请输入姓名:";
cin>>s;
while(cin.fail())
{
cout<<"输入错误!"<<endl<<"姓名必须是汉字或者英文字母!请检查后重试!"<<endl;
cin>>s;
}
ifstream infile("D:\\学生信息.txt",ios::binary);
if (!infile)
{
cerr<<"文件打开失败"<<endl;
exit(1);
}
infile.seekg(0,ios::beg);
for (int i=0;i<2;i++)
{
infile.read((char *)&a[i],sizeof(a[i]));
if (strcmp(s,a[i].name)==1)
{
j=1;
a[i].output();
}
if (j!=1)
cout<<"对不起，没有该姓名的学生!"<<endl;
}
}
void search_all_sex()
{
float number,j=0;
string s;
cout<<"请输入成绩:";
cin>>number;
while(cin.fail())
{
cout<<"输入错误!"<<endl<<"成绩必须是数字!请检查后重试!"<<endl;
cin>>number;
}
cout<<"请输入性别:";
cin>>s;
while(cin.fail())
{
cout<<"输入错误!"<<endl<<"性别只能是M(带便男性)或者F(代表女性)!请检查后重试!"<<endl;
cin>>s;
}
ifstream infile("D:\\学生信息.txt",ios::binary);
if (!infile)
{
cerr<<"文件打开失败"<<endl;
exit(1);
}
infile.seekg(0,ios::beg);
for (int i=0;i<2;i++)
{
infile.read((char *)&a[i],sizeof(a[i]));
if ((number==a[i].all)&&(strcmp(s,a[i].sex)==1))
{
j=1;
a[i].output();
}
if (j!=1)
cout<<"对不起，没有符合该条件的学生的学生!"<<endl;
}
}
void main()
{
cout<<"请输入学生人数";
cin>>n;
outfile.open("D:\\学生信息.txt",ios::out|ios::binary);
if(!outfile)
{
cerr<<"文件打开失败!"<<endl;
exit(1);
}
for (int i=0;i<n;i++)
a[i].input();
outfile.close();
for (i=0;i<2;i++)
a[i].output();
cout<<"请输入想要查询的方式："<<endl;
cout<<" 按学号查询请输入1，按姓名查询请输入2，按中成绩及性别查询请输入3"<<endl;
int m; //用于存放查询方式
cin>>m;
A:
switch(n)
{
case 1:
search_num();break;
case 2:
search_name();break;
case 3:
search_all_sex();break;
default:
{
cout<<"您输入的查询方式不正确，请重新输入"<<endl;
cout<<" 按学号查询请输入1，按姓名查询请输入2，按中成绩及性别查询请输入3"<<endl;
goto A;
}
}
char s;
cout<<"继续?(y/n)"<<endl;
cin>>s;
if (s=='y')
goto A;
else
{
cout<<"系统将退出，谢谢使用!"<<endl;
exit(0);
}
}
--------------------Configuration: 55 - Win32 Debug--------------------
Compiling...
55.cpp
D:\Micro\C++\安装包\MSDev98\MyProjects\5\55.cpp(26) : error C2390: '$S25' : incorrect storage class 'auto'
D:\Micro\C++\安装包\MSDev98\MyProjects\5\55.cpp(116) : error C2664: 'strcmp' : cannot convert parameter 1 from 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' to 'const char *'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
D:\Micro\C++\安装包\MSDev98\MyProjects\5\55.cpp(154) : error C2664: 'strcmp' : cannot convert parameter 1 from 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' to 'const char *'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
执行 cl.exe 时出错.
55.obj - 1 error(s), 0 warning(s)
