read roll no., marks, count pass and fail

Hi :)

I was trying to write a code to read roll no., marks, count pass, fail, A grade, B grade, etc. Do you find the code okay? As far as I could confirm it was working fine. I wanted your advice on those bold red braces which I want to use for clarification to show that the statements within those red braces are related. Can those red braces affect the the overall working? Please let me know. Thanks

Regards
Jackson

Code:

---

#include <iostream>
#include <cstdlib>

using namespace std;

int main()

{
  int rollno=0, pass=0, fail=0, Agrade=0, Bgrade=0, Cgrade=0, Dgrade=0, Egrade=0, Fgrade=0;
  float TM=0, OM=0;

  cout << "Enter total marks: ";
  cin >> TM;

  do
    {
        cout << "Enter Roll No. : ";
        cin >> rollno;

        cout << "Enter obtained marks: ";
        cin >> OM;

        {
        if (OM >= 0.5*TM)
            {
                pass = pass++;
            }
        else
            {
                fail = fail++;
            }
        }

        {
        if (OM >= 0.8*TM)
            {
                Agrade = Agrade++;
            }

        else if (OM >= 0.7*TM)
            {
                Bgrade = Bgrade++;
            }

        else if (OM >= 0.6*TM)
            {
                Cgrade = Cgrade++;
            }

        else if (OM >= 0.5*TM)
            {
                Dgrade = Dgrade++;
            }

        else if (OM >= 0.4*TM)
            {
                Egrade = Egrade++;
            }

        else
            {
                Fgrade = Fgrade++;
            }
        }

    }

    while (rollno > 0);

  cout << "Total pass is: " << pass << endl;
  cout << "Total fail is: " << fail << endl;
  cout << "Total A grades are: " << Agrade << endl;
  cout << "Total B grades are: " << Bgrade << endl;
  cout << "Total C grades are: " << Cgrade << endl;
  cout << "Total D grades are: " << Dgrade << endl;
  cout << "Total E grades are: " << Egrade << endl;
  cout << "Total F grades are: " << Fgrade << endl;

  system("pause");

}

---

They're not harmful in any way if that's what you're asking.

> I want to use for clarification to show that the statements within those red braces are related.
I would normally use a blank line and a comment to achieve the same thing.

Code:

---

        // calculate overall pass/fail
        if (OM >= 0.5*TM)
            {
                pass++;
            }
        else
            {
                fail++;
            }

        // calculate individual grades
        if (OM >= 0.8*TM)

---

> pass = pass++;
But all the statements like this are wrong, it's just
pass++;