有没有办法在参数化构造函数中输入10个学生的详细信息，并使用c++中带有对象数组的成员函数打印出来

Question

我尝试过这段代码，但当我在循环内调用成员函数时，它会给出详细信息的垃圾值，而当我在环外调用成员函数，它会给我错误。

#include<iostream>
#include<string.h>
using namespace std;
class student
{   
char name[10];
int id,rollno;
public:
student(char name[10],int id,int rollno)
{
strcpy(this->name,name);
this->id=id;
this->rollno=rollno;
cout<<"the name of the student is:"<<name<<endl;
cout<<"the id of the student is:"<<id<<endl;
cout<<"the roll no of the student is:"<<rollno<<endl;
}
};
int main()
{
int id1,rollno1;
char name1[10];
for(int i=1;i<=2;i++)
{  
cout<<"             enter the detail of the student "<<i<<"                       "<<endl;
cout<<"enter the name of the student:";
cin>>name1;
cout<<"enter the id of the student:";
cin>>id1;  
cout<<"enter the roll no of the student:";
cin>>rollno1;
student d[]={student(name1,id1,rollno1)};
d[i].print();
}
return 0;
}

Answer 1

下面是您的代码回顾。

#include <iostream> 
#include <string.h>
using namespace std; // it is strongly suggested that you don't use the whole header unless your intent is speeding up coding
class Student // capitalize classes
{
char _name[10];// it is ok, however, if you use the <string> header, why would you go back to char type?
int _id, _rollno;
public:
Student(char name[10] /* this is just the array's first item passed! */, int id, int rollno)
{
// Don't use this->, use an underscore for one of the names. 
// I use underscores for the encapsulated data
strncpy_s(_name, name, 9);// a safer version
_id = id; 
_rollno = rollno;
cout << "nCtor says: ";
cout << "the name of the student is: " << _name << endl;
cout << "the id of the student is: " << _id << endl;
cout << "the roll no of the student is: " << _rollno << endl;
cout << 'n';
}
const char* getName() { return _name; }
const int getId() { return _id; }
const int getRollNo() { return _rollno; }
// unless you overload operator<< , you have to make getters for your info, or make it public
};
int main()
{
int id, rollno;// why 1? they won't intersect with the function
char name[10];
Student *s[2];//you must make that on the heap; otherwise you need a default constructor
for (int i{ 0 }; i < 2; i++)// start with 0 and make it just <
{
cout << "enter the details of the student " << i << endl;// Why so many spaces?
cout << "enter the name of the student: "; // add space after the colon
cin >> name;// remember, you're limited to 9 chars + n !!!
cout << "enter the id of the student: ";
cin >> id;
cout << "enter the roll no of the student: ";
cin >> rollno;
//student d[] = { student(name,id,rollno) }; // you can't do this. It's not flexible.
// You either assign enough space for the intended number of students in the stack, statically, or 
// you lett it find more space in the heap = dynamically
//this goes to the heap
s[i]= new Student( name,id,rollno );// parentheses are well
//s[i] = new Student{ name,id,rollno };// initializer list may also do
//d[i].print();// what's to print here? It's not POD, cout needs instructions
cout << "Stored data -> Id: " << 
s[i]->getId() << ", Name: "  // -> dereferences the pointer, and s is a pointer now
<< s[i]->getName() << ", Roll no: " 
// or you can dereference it
<< (*s[i]).getRollNo() 
<< endl << endl; // make some extra space here

}
return 0;
}