Error rectification

[Bluefree]

Can you help rectify two errors in the following program:
1. Statement missing ;
2. Declaration terminated incorrectly

#include<iostream.h>
#include<stdio.h>
#include<conio.h>
class student
{
 int rollno;
 char name[25];
 char grade;
 float marks;
 public: void readstudent()
 
 {
  cout<<"Enter the rollno.:";
  cin>>rollno;
  cout<<"\nEnter the name:";
  gets(name);
  cout<<"\nEnter the marks:";
  cin>>marks;
  }
   void disstudent()
   {
    cgrade();
    cout<<"\nRollno:"<<rollno;
    cout<<"\nName:"<<name;
    cout<<"\nMArks:"<<marks;
    cout<<"\nGrade:"<<grade;
    }
    int getrollno()
    {
     return rollno;
     }
    float getmarks()
    {
     return marks;
     }
    void cgrade()
    {
     if(marks>=75)
     {
      grade='O';
      }
     else if(marks>=60)
     {
      grade='A';
      }
     else (marks>=40)
     {
      grade='F';
      }
      }
 
   void main()
   {
    clrscr();
    student s[3];
    for (int i=0;i<3; i++)
    {
     cout<<"Enter details of student"<<i+1<<":";
     s[i].readstudent();
     }
      int ch,rno,pos=-1,highmarks=0;
      do{
     cout<<"Main Menu \n 1.Specific student\n 2.Topper\n 3.Exit \n Enter the choice:\n";
     cin>>ch;
     switch(ch)
     {
      case 1: cout<<"Enter the rollno:\n";
      cin>>rno;
      for(int i=0;i<3;i++)
      {
       if (s[i].getrollno()==rno)
       {
        s[i].disstudent();
        break;
        }
       }
        if(i==10)
        {
         cout<<"Invalid";
         }
      case 2: for(i=0;i<3;i++)
      {
       if (s[i].getmarks()>highmarks)
        {
         pos=i;
         highmarks=s[i].getmarks();
         }
        }
         s[i].disstudent();
         break;
      case 3: break;
      default: cout<<"Wrong";
      break;
     }
    }
     while(ch>=1&&ch<3);
     getch();
    }
 }
 

[weaknessforcats]

You have mismatched braces. It looks like the main() is inside the class definition. There's one place where you have
"if (i == 10)" but there is no i variable defined.

The class definition does not end with a ;.