This is the full of code, can you tells me that what should me need to change for proper execution
Code:
#include <iostream.h>
using namespace std;
main()
{                                     //Initialization of veriables
      char grad;                     //to take inputs of grades A or B
      int tnos, ga, gb;              
      tnos = 1;                      //Total number of students
      ga = 0;                        //Total number of grad 'a'
      gb = 0;                        //Total number of grad 'b'
      do
      {
           cout<<"Enter the Grade of Student "<<tnos<<" :";    //to take inputs
                 cin>>grad;
                 if(grad=='a')            //to decide while the grade is 'a', 'b' or anyother
                 {
                         ga=ga+1;            //counter to count 'a' grades
                         tnos=tnos+1;
                         }
                 else if(grad=='b')
                 {
                              gb=gb+1;          //counter to count 'b' grades
                              tnos=tnos+1;
                              }
                 else
                 {
                     cout<<"Please enter only grads A or B:";
                     }
                     }
                     while(tnos<=10);               //maximum inputs to take or total number of students whos grades are required
                                {
                                     cout<<"Total A grades are : "<<ga;
                                     cout<<"Total B grades are : "<<gb;
                                     }
                                     
                                     //Now on the basis of total number of grades we shell show the status of a class.
                                     
                                     if(ga<=2)
                                     cout<<"Your class is Poor..!";
                                     else if(ga<=7)
                                     cout<<"Your class is Good..!";
                                     else
                                     cout<<"Your class is Brilliant..!";
                 }
it takes the input correctly but close cmd window before showing the result.