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Example Program: Student Mark Processing (2)

The program in section 16.5 could have equally well have been written using a do-while loop. The do-while loop would be:

cin >> candno;
do {
    // enter marks
  cout << "Input candidate marks: ";
  cin >> s1 >> cw1 >> s2 >> cw2;
    // process marks
  count = count+1;
  final1 = int(EXAMPC*s1+CWPC*cw1);
  final2 = int(EXAMPC*s2+CWPC*cw2);
  sum1 = sum1+final1;
  sum2 = sum2+final2;
    // output marks
  cout << candno << " "
       << s1 << " " << cw1 << " "
       << s2 << " " << cw2 << " "
       << final1 << " " << final2
       << endl;
    // enter candidate number
  cout << "Input candidate number (negative to finish): ";
  cin >> candno;
  } while (candno >= 0);
Download program.

This is not completely equivalent to the while statement version. Consider what happens if the user initially enters a negative candidate number--they would be surprised to then be asked for further data and another candidate number! If there is at least one candidate then the two versions are equivalent.


Next: Summary Up: The do-while statement Previous: Example Program: Valid Input