关于结构体改成类的问题 怎么实现呢

Question

如果雇员定义的是一个类（结构体改成类
怎么用文件呢

//1） 将五名员工的数据（包括员工编号、姓名、年龄和工资）按员工编号从小到大的顺序输出到磁盘文件中保存。
//（2） 从键盘输入一名员工的数据（员工编号大于现有员工编号），并将其添加到文件末尾。
//（3） 输出文件中所有员工的数据。
//（4） 从键盘输入一个数字，以确定文件中是否有此员工编号。如果是，将显示该员工的所有数据。如果没有，则输出“无人发现”。您可以重复查询。如果输入的员工编号为0，则查询将结束。
#include<bits/stdc++.h>
#include <fstream>
using namespace std;
struct staff{
    int num;
    char name[20];
    int age;
    double salary;
};
int main(){
    staff staff_[7]={
    2001,"Li",25,8500,
    2002,"Wang",26,9000,
    2003,"Zhang",27,9500,
    2004,"Liu",28,9600,
    2005,"Zheng",26,10000.1},staff_1;
    fstream iofile("staff.dat",ios::in | ios::out|ios::binary); //以读写模式打开
    if(!iofile){ //用is_open()判断是否打开
        cerr<<"open error!"<<endl;
        abort();
    }
    int num;
    cout<<"Five staff:"<<endl;
    for(int i=0;i<5;i++){
        cout<<staff_[i].num<<" "<<staff_[i].name<<" "<<staff_[i].age<<" "<<staff_[i].salary<<endl;
        iofile.write((char*)&staff_[i],sizeof(staff_[i]));//写入文件 
    }
    cout<<"Please input the staff's information that you want to insert"<<endl;
        cin>>staff_1.num>>staff_1.name>>staff_1.age>>staff_1.salary;
        iofile.write((char*)&staff_1,sizeof(staff_1));
    cout<<"All the staff"<<endl;
 
    iofile.seekg(0,ios::beg);
    int ntotal = 0;
    while(!iofile.eof())
    { //这里用eof判断是否读取结束
        iofile.read((char*)&staff_[ntotal],sizeof(staff_[ntotal]));
        
        if(staff_[ntotal].num > 0 && staff_[ntotal].age>0 && staff_[ntotal].salary>0)
        {
            cout<<staff_[ntotal].num<<" "<<staff_[ntotal].name<<" "<<staff_[ntotal].age<<" "<<staff_[ntotal].salary<<endl;
            ntotal++;
        }
    }
    iofile.close();
    cout<<"Please input the number that you want to search"<<endl;
    cin>>num;
    int flag=0;
    while(flag ==0)
    {
        for(int i=0;i<ntotal;i++){
            if(num==staff_[i].num){
                cout<<num<<"is No."<<i+1<<endl;
                cout<<staff_[i].num<<" "<<staff_[i].name<<" "<<staff_[i].age<<" "<<staff_[i].salary<<endl;
                flag=1;
                break;
            }
        }
        if(flag==0){
            cout<<"can't find!"<<endl;
            cout<<"Please input again or enter 0 to stop!"<<endl;
            cin>>num;
        }
    }
    
    
    return 0;
}

Answer 1

供参考

class staff{
private:
    int num;
    char name[20];
    int age;
    double salary;

public:
    staff();
    staff(int vnum,char *vname,int vage,double vsalary);
    void print();
};

staff::staff()
{
    num=age=0;
    salary=0;
    memset(name,0,20);
}
    
staff::ssaff(int vnum,char *vname,int vage,double vsalary)
{
    num=vnum;
    strcpy(name,vname);
    age=vage;
    salary=vsalary;
}

void staff::print()
{
    cout<<num<<" "<<name<<" "<<age<<" "<<salary<<endl;
}