create a c++ class for student having following members

/*create a c++ class for student having following members.
-rollno
-name
-number of marks
-marks of each subject
(number of marks varies for each student)
write a parameterised constructor which initialise rollno, name and number
of subject and create the array of marks dynamically. display all
student with percentage and class obtain*/
#include<conio.h>
#include<string.h>
#include<iostream.h>
class student
{
int rno,nos,marks[10];
char name[20];
public:student(int r,char n[20],int no);
       void display();

};
student::student(int r,char n[20],int no)
       {
    int i;
    int *p;
    p=new int[no];
    cout<<"\nenter marks of "<<no<<"  subject:-";
    for(i=0;i<no;i++)
    {
    cin>>p[i];
    marks[i]=p[i];
    }
    rno=r;
    strcpy(name,n);
    nos=no;
    }
void student::display()
    {
    int i,sum=0,tot;
    float per;
    cout<<"\nrollno:-"<<rno<<"\nname:-"<<name
    <<"\nnumber of subject:-"<<nos;
    for(i=0;i<nos;i++)
    {
    cout<<"\nmarks"<<i+1<<":-"<<marks[i];
    sum=sum+marks[i];
    }
    tot=nos*100;
    per=((float)sum/tot)*100;
    cout<<"\npercentage:-"<<per;
    if(per>75)
    cout<<"\nclass:-A";
    else
    if(per>60&&per<75)
    cout<<"\nclass:-B";
    else
    if(per>35&&per<60)
    cout<<"\nclass:-C";
    else
    cout<<"\nclass:-fail";
    }
int main()
{
int r,no;
char n[20];
clrscr();
cout<<"\nfor 1st student\n";
student s1(101,"amar",3);
cout<<"\nfor 2nd student\n";
student s2(102,"ajay",4);
cout<<"\nfor 3rd student\n";
student s3(103,"akbar",2);
cout<<"\n\ndetails of all student\n";
s1.display();
s2.display();
s3.display();
getch();
return 0;
}
/*

for 1st student                                                                
                                                                               
enter marks of 3  subject:-12                                                  
12                                                                             
23
                                                                               
for 2nd student                                                                
                                                                               
enter marks of 4  subject:-23                                                  
34                                                                             
12                                                                             
11                                                                             
                                                                               
for 3rd student                                                                
                                                                               
enter marks of 2  subject:-77                                                  
66                                                                             
                                                                               
                                                                               
details of all student
                                                                               
rollno:-101                                                                    
name:-amar                                                                     
number of subject:-3                                                           
marks1:-12
marks2:-12                                                                     
marks3:-23                                                                     
percentage:-15.666667                                                          
class:-fail                                                                    
rollno:-102                                                                    
name:-ajay                                                                     
number of subject:-4                                                           
marks1:-23                                                                     
marks2:-34                                                                     
marks3:-12                                                                     
marks4:-11                                                                     
percentage:-20                                                                 
class:-fail                                                                    
rollno:-103                                                                    
name:-akbar
number of subject:-2
marks1:-77
marks2:-66
percentage:-71.5
class:-B
*/