(Validating User Input) The examination-results program of Fif. 3.12 assumes that any val- ue input by the user that is not a 1 must be a 2. Modify the application to validate its inputs. On any input, if the value entered is other than 1 or 2, keep looping until the user enters a correct value.

Question

What will be an ideal response?

Answer 1

```
// Examination results problem: Validating input.
#include
using namespace std;

int main()
{
// initializing variables in declarations
int passes = 0; // number of passes
int failures = 0; // number of failures
int studentCounter = 1; // student counter
int result; // one exam result (1 = pass, 2 = fail)

// process 10 students using counter-controlled loop
while ( studentCounter <= 10 )
{
// prompt user for input and obtain value from user
cout << "Enter result (1 = pass, 2 = fail): ";
cin >> result; // input result

if ( result == 1 ) // 1 is a valid input
{
passes = passes + 1; // increment passes
studentCounter = studentCounter + 1; // increment studentCounter
} // end if
else if ( result == 2 ) // 2 is a valid input
{
failures = failures + 1; // increment failures
studentCounter = studentCounter + 1; // increment studentCounter
} // end else if
else // invalid input; tell user and prompt again
{
cout << "Invalid input" << endl;
} // end else
} // end while

// termination phase; display number of passes and failures
cout << "Passed " << passes << "\nFailed " << failures << endl;

// determine whether more than eight students passed
if ( passes > 8 )
cout << "Bonus to instructor!" << endl;
} // end main
```