Write a C++ program to find average marks of N student each having M subjects in a class.

#include<iostream.h> 
 #include<conio.h> 
 #include<dos.h> 
 void main ( ) 
  { 
                struct student 
            { 
                int rn ; 
                int sub[10] ; 
             }; 
                  struct student st[50] ; 
                  int i, j,n,m,total; 
                  float av; 
                  clrscr( ); 
                  cout<<"\n Enter the Number of Students in the Class : "; 
                  cin>> n ; 
                  cout<<"\nEnter the Number of Subjects Each Student has Taken : " ; 
                  cin>> m ; 
                  for (i=0;i<n;i++) 
                   { 
                          total = 0 ; 
                          cout<<"\nEnter the Rollno of "<<i+1<<" Student : "; 
                          cin>> st[i].rn; 
                          cout<<"\nEnter the Marks : "; 
                          for (j=0;j<m;j++) 
                               { 
                                     cout<<"\nEnter the Marks of "<<j+1 <<" Subject : "; 
                                     cin>> st[i ].sub[j ]; 
                                     total = total + st[i ].sub[j ]; 
                               } 
                                     av = (float) total / m ; 
                                     cout<<"AVERAGE Marks of "<<i+1<<" Student = "<< av; 
                        } 
                                     getch(); 
 }