Write A C++ Program To Compute Average Marks Of N Students.

#include<iostream.h>
#include<conio.h>
struct student
{
       int rn;
       int sub[3];
       int av;
}res;
    student input(student x[ ], int y);
    void display(student x[ ], int y);
           void main()
       {
           student m[100];
           int n,i;
           clrscr();
           cout<<"\n How many students in the class: ";
           cin>>n;
           cout<<"\n Enter the data:";
           for(i=0;i<n;i++ )
               {
                     m[i]=input(m, i);
               }
                    display(m,n);
                    getch();
       }
            student input(student m[ ], int i)
       {
              int j;
             float tm=0;
             cout<<"\n Enter Rollno and marks :";
             cin>>m[i].rn;
             for( j=0;j<3;j++ )
                 {
                    cin>>m[i].sub[j];
                    tm= tm+m[i].sub[j];
                }
                    m[i].av=tm/3;
                    j=0;
                    return m[i];
      }
                    void display(student m[ ], int n)
                    {
                         int j,k;
                         cout<<"\n RESULT IS:";
                         cout<<"\n ROLLNO 1 2 3 Average of Marks";
                         for(j=0;j<n;j++ )
                             {
                                cout<<m[j].rn<<"\t";
                                for(k=0;k<3;k++ )
                                    {
                                        cout<<m[j].sub[k]<<" ";
                                        cout<<"\t" <<m[j].av<<endl;
                                    }
                            }
                                         return;
                   }