Bool must be always returning NULL(if statement ignoring true or false) - c++11

Question

I need to know why I am always returning NULL in the following context(for example no matter if I say "Yes", or "No", for any of the questions I am getting null( I assume because the question process repeats when it runs) even though I say no in main. I'm trying to get it to do this: for all invalid answers I return null, if null start over the question process, if answer was valid I return either true or false, if true continue, if false quit program.
bool question1()
{
string answer2;
cout << "Are you 18 or older and have a valid Driver's License? Yes or No: ";
getline( cin, answer2);
transform(answer2.begin(), answer2.end(), answer2.begin(), ::tolower);
cout << endl;
if( answer2 == "yes")
{
cout << "Alright! " << endl << "You are set for registration. Please fill out the registration form. ";
return true;
}
else if( answer2 == "no")
{
cout << "Do you know someone else who is 18 or older that can register? Yes or No ";
getline( cin, answer2);
transform(answer2.begin(), answer2.end(), answer2.begin(), ::tolower);
if( answer2 == "yes")
{
cout << "Good, then please continue the process in their place. Please fill out the registration form";
return true;
}
else if( answer2 == "no")
{
cout << "Please come back later when you have the appropriate personel";
return false;
}
else
{
cout << "The answer given was invalid. Please give a valid answer. " << endl << endl ;
return NULL;
}
}
else
{
cout << "The answer given was invalid. Please give a valid answer. " << endl << endl;
return NULL;
}
void registerPerson( array< string, nameSize > namesOfPeople, array< string, idSize > idlen)
{
string pName;
string dLicense;
static int i = 0;
static int b = 0;
static int c = 0;
unsigned int x = 1;
cout << endl << endl << "REGISTRATION FORM:" << endl << endl << "------------------" << endl;
cout << "Please" << endl << "enter the following: \n \n";
cout << "Name: ";
getline( cin, pName );
for ( int j = i; j<=800; ++ j )
{
namesOfPeople[j] = pName;
cout << namesOfPeople[j];
i = i + 1;
break;
}
cout << endl;
while( x = 1)
{
cout << "Driver\'s Licence Number( Must be 9 characters long, no dashesh ): ";
cin >> dLicense;
if ( dLicense.length() < 9 || dLicense.length()> 9 )
{
cout << "The entered number was invalid. Please try again";
}
else
{
for ( int a = i; c<=800; ++ a )
{
idlen[a] = dLicense;
cout << idlen[a];
c = c + 1;
break;
}
}
}
}
}
{
int main()
array< string, nameSize > names = {};
array< string, idSize > ids = {};
carShare mycarShare1;
carShare mycarShare2;
mycarShare2.welcomeMessage();
mycarShare2.question1();
if( mycarShare1.question1() == NULL)
{
mycarShare1.question1();
}
else if( mycarShare1.question1() == true)
{
mycarShare1.registerPerson(names, ids);
}
else
{
return 0;
}
system( "PAUSE" );
return 0;
}

Answer 1

I'd probably change it to handle invalid input within question1() itself. An easy way to start the question over again is letting question1 call itself again on invalid input until it gets a valid one like here (I put comments at all the changed places.):
bool question1()
{
string answer2;
cout << "Are you 18 or older and have a valid Driver's License? Yes or No: ";
getline( cin, answer2);
transform(answer2.begin(), answer2.end(), answer2.begin(), ::tolower);
cout << endl;
if( answer2 == "yes")
{
cout << "Alright! " << endl << "You are set for registration. Please fill out the registration form. ";
return true;
}
else if( answer2 == "no")
{
cout << "Do you know someone else who is 18 or older that can register? Yes or No ";
getline( cin, answer2);
transform(answer2.begin(), answer2.end(), answer2.begin(), ::tolower);
if( answer2 == "yes")
{
cout << "Good, then please continue the process in their place. Please fill out the registration form";
return true;
}
else if( answer2 == "no")
{
cout << "Please come back later when you have the appropriate personel";
return false;
}
else
{
cout << "The answer given was invalid. Please give a valid answer. " << endl << endl ;
return question1(); // call itself again on invalid input.
}
}
else
{
cout << "The answer given was invalid. Please give a valid answer. " << endl << endl;
return question1(); // call itself again on invalid input.
}
}
int main()
{
array< string, nameSize > names = {};
array< string, idSize > ids = {};
carShare mycarShare1;
carShare mycarShare2;
mycarShare2.welcomeMessage();
bool answer = mycarShare2.question1();
/* if( answer == NULL) we don't need this anymore if we handle errors inside question1()
{
mycarShare1.question1();
}
*/
if( answer == true) // notice the change to if instead of else if here.
{
mycarShare1.registerPerson(names, ids);
}
else
{
return 0;
}
system( "PAUSE" );
return 0;
}
Another way to do the same without recursion would be a do... while loop, here's a version of only question1() with a loop:
bool question1()
{
string answer2; // has to be declared before the loop.
do
{
cout << "Are you 18 or older and have a valid Driver's License? Yes or No: ";
getline( cin, answer2);
transform(answer2.begin(), answer2.end(), answer2.begin(), ::tolower);
cout << endl;
if( answer2 == "yes")
{
cout << "Alright! " << endl << "You are set for registration. Please fill out the registration form. ";
return true;
}
else if( answer2 == "no")
{
cout << "Do you know someone else who is 18 or older that can register? Yes or No ";
getline( cin, answer2);
transform(answer2.begin(), answer2.end(), answer2.begin(), ::tolower);
if( answer2 == "yes")
{
cout << "Good, then please continue the process in their place. Please fill out the registration form";
return true;
}
else if( answer2 == "no")
{
cout << "Please come back later when you have the appropriate personel";
return false;
}
}
}while(answer2 != "yes" && answer2 != "no"); // loop as long as the input is invalid.
}
=====================================
Edit:
As clarification to it printing multiple times, here's the culprit in your original code:
mycarShare2.question1();
if( mycarShare1.question1() == NULL)
{
mycarShare1.question1();
}
else if( mycarShare1.question1() == true)
{
mycarShare1.registerPerson(names, ids);
}
else
{
return 0;
}
mycarShare2.question1() is a function call, you were calling your function 3 times in that part. What you'd want was probably saving it in a bool variable and only test in the if/else statements after that, like this:
bool answer = mycarShare2.question1();
if( answer == NULL)
{
mycarShare1.question1();
}
else if( answer == true)
{
mycarShare1.registerPerson(names, ids);
}
else
{
return 0;
}
Note: this is just to show it the way you probably expected it to be executed in your original code and not a solution. As said bool can only be true or false and the check for NULL isn't needed at all. (See my solutions above.)