how to read the integer member variable

[V8cTor]

this program is not giving to chance to enter the ooplevel value.please help

#include <iostream>
using namespace std;
const int SLEN = 30;
struct student {
	char fullname[SLEN];
	char hobby[SLEN];
	int ooplevel;
};
// getinfo() has two arguments: a pointer to the first element of
// an array of student structures and an int representing the
// number of elements of the array. The function solicits and
// stores data about students. It terminates input upon filling
// the array or upon encountering a blank line for the student
// name. The function returns the actual number of array elements
// filled.
int getinfo(student pa[], int n);
// display1() takes a student structure as an argument
// and displays its contents
void display1(student st);
// display2() takes the address of student structure as an
// argument and displays the structure’s contents
void display2(const student * ps);
// display3() takes the address of the first element of an array
// of student structures and the number of array elements as
// arguments and displays the contents of the structures
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)
{
	int num = 0;
	int i;
	for (i = 0; i < n; i++)
	{
		cout << "for student " << i + 1 << ":\n";
		cout << "enter fullname:\n";
		cin.getline(pa[i].fullname, SLEN);
		if (!strcmp(pa[i].fullname, "\n"))break;
		num++;
		cout << "enter hobby:\n";
		cin.getline(pa[i].hobby, SLEN);
		cout << "enter ooplevel: ";
		while (!cin >> pa[i].ooplevel)
		{
			cin.clear();
			while (cin.get() != '\n');
			cout << "Bad input.\n";
			cout << "enter ooplevel: ";
		}
	}
	return num;
}
void display1(student st)
{
	cout << "fullname: " << st.fullname << endl;
	cout << "hobby: " << st.hobby << endl;
	cout << "ooplevel: " << st.ooplevel << endl << endl;
}
void display2(const student * ps)
{
	cout << "fullname: " << ps->fullname << endl;
	cout << "hobby: " << ps->hobby << endl;
	cout << "ooplevel: " << ps->ooplevel << endl << endl;
}
void display3(const student pa[], int n)
{
	int i;
	for (i = 0; i<n; i++)
	{
		cout << "for student " << i + 1 << ":\n";
		cout << "fullname: " << pa[i].fullname << endl;
		cout << "hobby: " << pa[i].hobby << endl;
		cout << "ooplevel: " << pa[i].ooplevel << endl << endl;
	}
}

[V8cTor]

while (!cin >> pa[i].ooplevel)
		{
			cin.clear();
			while (cin.get() != '\n');
			cout << "Bad input.\n";
			cout << "enter ooplevel: ";
		}

the code is for reading valid number values.

[Elysia]

Reading some non-string type and then a string type from std::cin causes problems because reading a non-type leaves a newline in the input buffer but strings happily consume this newline and does not ask for additional input.
See how to clear the input buffer.

>> char fullname[SLEN];
>> char hobby[SLEN];
Use std::string, i.e.:
std::string fullname;
std::string hobby;

>>student * ptr_stu = new student[class_size];
Use std::vector, i.e.
std::vector<student> Students(class_size);

>>display1(ptr_stu[i]);
Assuming you used std::vector, use Students.at(i). Then you will know if you've accessed a record that does not exist (the [] operator causes undefined behavior if you access undefined elements).

>>void display1(student st)
Rule of thumb: Pass structures by const reference, i.e. void display(const student& st).

>>while (!cin >> pa[i].ooplevel)
! binds tigher than >>, so this means while ((!cin) >> pa[i].ooplevel) which is highly unlikely what you want! Add parenthesises to change the evaluation order, i.e. while (!(cin >> pa[i].ooplevel)).

>> int i;
>> for (i = 0; i<n; i++)
Since the variable is only going to be used inside the loop (typical with loop variables), declare it inside the loop, i.e. for (int i = 0; i<n; i++).

[V8cTor]

yeah, i didn't add the required parenthesis.thanks Elysia.