c++ 定义一个结构体student，输入多个student的信息并以三种方式显示

#include <iostream>
#include <string>
using namespace std;
const int slen = 30;
struct student {
	char fullname[slen];
	char hobby[slen];
	int ooplevel;
};

int getinfo(student pa[], int n);

void display1(student st);

void display2(const student * ps);

void display3(const student pa[], int n);

int main() {
	cout << "enter class size: ";
	int class_size;
	cin >> class_size;
	while (cin.get() != '\n')
		continue;

	student * ptr_stu = new student[class_size];
	int entered = getinfo(ptr_stu, class_size);
	for (int i = 0; i < entered; i++) {
		display1(ptr_stu[i]);
		display2(&ptr_stu[i]);
	}
	display3(ptr_stu, entered);
	delete[] ptr_stu;
	cout << "done\n";
	return 0;
}

int getinfo(student pa[], int n) {
	for (int i = 0; i < n; i++) {
		cout << "#" << i + 1 << " fullname: ";
		cin.getline(pa[i].fullname, slen);
		cout << "#" << i + 1 << " hobby: ";
		cin.getline(pa[i].hobby, slen);
		cout << "#" << i + 1 << " ooplevel: ";
		(cin >> pa[i].ooplevel).get();
		cout << endl;
	}
	return n;
}

void display1(student st) {
	cout << "fullname: " << st.fullname << endl;
	cout << "hobby: " << st.hobby << endl;
	cout << "ooplevel: " << st.ooplevel << endl;
}

void display2(const student * ps) {
	cout << "fullname: " << ps->fullname << endl;
	cout << "hobby: " << ps->hobby << endl;
	cout << "ooplevel: " << ps->ooplevel << endl;
}

void display3(const student pa[], int n) {
	for (int i = 0; i < n; i++) {
		display2(&pa[i]);
	}
}