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How to get Average

gongong (80)
how would i calculate the average and call getAverage() in main?

i get that we need to get the mean of the user input
ratedTerrible, //0
ratedBad, //25
ratedOK, //50
ratedGood, //75
ratedGreat; //100

sum up the total of user input then divide by (20 * numberOfTimesRated)
e.g.
user1 rate: 3
user2 rate: 5
user3 rate: 4

average = (50 + 100 + 75) / (20 * 3)

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#include <iostream>
#include <string>
#include "input.h"


using namespace std;
class Movie
{
private:
	string name,
		MPAA_Rating;
	int ratedTerrible, //1
		ratedBad, //2
		ratedOK, //3
		ratedGood, //4
		ratedGreat; //5
public:
	Movie();
	Movie(string name, string MPAA_Rating);

	string getName()const;
	void setName(string name);

	string getMPAA_Rating()const;
	void setMPAA_Rating(string MPAA_Rating);

	void addRating(int r);

	double getAverage()const;
};
Movie::Movie() : 
	ratedTerrible(0), 
	ratedBad(0), 
	ratedOK(0), 
	ratedGood(0), 
	ratedGreat(0), 
	name(""), 
	MPAA_Rating(""){};
Movie::Movie(string name, string MPAA_Rating)
{
	this->name = name;
	this->MPAA_Rating = MPAA_Rating;
}
void Movie::setName(string name)
{
	this->name = name;
}
string Movie::getName()const
{
	return name;
}
void Movie::setMPAA_Rating(string MPAA_Rating)
{
	if(MPAA_Rating == "G" || 
		MPAA_Rating == "PG" || 
		MPAA_Rating == "PG-13" || 
		MPAA_Rating == "R")
		this->MPAA_Rating = MPAA_Rating;
	else
		this->MPAA_Rating = "UNRATED";
}
string Movie::getMPAA_Rating()const
{
	return MPAA_Rating;
}

void Movie::addRating(int r)
{
	if (r == 1)
		ratedTerrible = 0;
	else if (r == 2)
		ratedBad = 25;
	else if (r == 3)
		ratedOK = 50;
	else if (r == 4)
		ratedGood = 75;
	else if (r == 5)
		ratedGreat = 100;
	else
		return;
}
double Movie::getAverage()const
{
	double average = 0;

	return 0;
}

int main()
{
	Movie movieRatings;
	string movieTitle, mpaaRating;

	cout << "Enter a movie title: ";
	cin >> movieTitle;
	movieRatings.setName(movieTitle);

	cout << "Enter MPAA Rating (G || PG || PG-13 || R): ";
	cin >> mpaaRating;
	movieRatings.setMPAA_Rating(toUpper(mpaaRating));


	char ans;
	do
	{
		int movieRating = inputInteger("Enter rating (1-Terrible, 2-Bad, 3-OK, 4-Good, 5-Great): ", 1, 5);
		movieRatings.addRating(movieRating);
		cout << "You rated " << movieTitle << " a " << movieRating << endl;

		ans = inputChar("Add another rating (Y||N)? ", 'y', 'n');

	} while (ans == 'y');


	//output
	cout << "TITLE: " << movieRatings.getName() << endl;
	cout << "MPAA_RATING: " << movieRatings.getMPAA_Rating() << endl;
	cout << "RATING: " << movieRatings.getAverage();
}

//just some validation function that you may want to move up before main if you wish to run the code...
char inputChar(string prompt, char yes, char no)
{
	char input;
	do
	{
		cout << prompt;
		if (!(cin >> input))
		{
			cout << "ERROR-1A: Invalid input. Must be a character type.\n";
			cin.clear();
			cin.ignore(999, '\n');
		}
		else if (tolower(input) != tolower(yes) && tolower(input) != tolower(no))
			cout << "ERROR-2A: Invalid input. Must be a '" << static_cast<char>(toupper(yes)) << "' or '" << static_cast<char>(toupper(no)) << "' character.\n";
		else
			break;
	} while (true);
	return input;
}

int inputInteger(string prompt, int startRange, int endRange)
{

	int input;
	do
	{
		cout << prompt;
		if (!(cin >> input))
		{
			cout << "ERROR-3A: Invalid input. Must be an integer type.\n";
			cin.clear();
			cin.ignore(999, '\n');
		}
		else if (!(input >= min(startRange, endRange) && input <= max(startRange, endRange)))
			cout << "ERROR-3A: Invalid input. Must be from " << startRange << "..." << endRange << ".\n";
		else
			break;
	} while (true);
	return input;
}
string toUpper(string str)
{
	for (int i = 0; i < str.length(); i++)
	{
		str.at(i) = toupper(str.at(i));
	}
	return str;
}
MikeyBoy (5631)
how would i calculate the average

Divide the sum of all the ratings, by the number of ratings.

and call getAverage() in main?

Um... just call it? I'm unclear what you're asking here.

Your addRating() function doesn't make much sense. All you're doing is setting the number of a different global variable depending on what r is. Each variable is only ever set to one constant, hardcoded number, and you never then do anything with those variables, so... what's the point of it?

You need to sit down and think clearly about your logic. Stop writing code, and just think about how you'd calculate this using a pen and paper. Once you've got the logic clear, only then should you start writing code.
Last edited on
Handy Andy (5051)
Hello gongong,

When I tried to compile your program my compiler complained about "input.h" and could not find this file.

I suspect that "input.h" is like "iostream.h". Both are very old and no longer supported or used.

In the "inputInteger" function the functions "min" and "max" were not defined. This may have come from the "input.h" header file that I do not have. I, for now have used the "Windows.h" header, but that is not the answer.

You line of code:
else if (!(input >= min(startRange, endRange) && input <= max(startRange, endRange))) could be written as:else if (!(input >= startRange && input <= endRange)).

Beyond that I will have to test the program. Using only one object of "Movie" it looks like you will have a problem trying to figure an average, but at this point I am not sure what you are trying to do.

Hope that helps,

Andy
gongong (80)
Hi,

@Andy
input.h is a header file i use for validations. just remove #include “input.h” and replace with #include <algorithm> bc algorithm is the library that has min and max
I’ve actually included those functions toward the end. moving them above main

@Mikey
I’m most likely overthinking this. I’ll do what you suggested and get back to this thread in a bit

Thanks for the reply, people :3
Handy Andy (5051)
Hello gongong,

My apologies. When I say the (input.h) I missed the double quotes and my brain went elsewhere.

In that case and since it is a header file that you wrote, please include it with your program so everyone can see if there are any problems in it. Also it allows your program to compile properly.

This is your program that I have made some changes to, but mostly what you started with:
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#include <cctype>  //<--- Added.
#include <iostream>
#include <iomanip>  //<--- Added.
#include <limits>  //<--- Added.
#include <string>

//#include "input.h"

using namespace std;  // <--- Best not to use.
// A recent post that is worth reading. http://www.cplusplus.com/forum/beginner/258335/

class Movie
{
	private:
		string name,
			MPAA_Rating;
		int ratedTerrible, //1
			ratedBad,      //2
			ratedOK,       //3
			ratedGood,     //4
			ratedGreat;    //5
	public:
		Movie();
		Movie(string name, string MPAA_Rating);

		string getName()const;
		void setName(string name);

		string getMPAA_Rating()const;
		void setMPAA_Rating(string MPAA_Rating);

		void addRating(int r);

		double getAverage()const;
};

Movie::Movie() :
	ratedTerrible(0),
	ratedBad(0),
	ratedOK(0),
	ratedGood(0),
	ratedGreat(0),
	name(""),
	MPAA_Rating("") {};

Movie::Movie(string name, string MPAA_Rating)
{
	this->name = name;
	this->MPAA_Rating = MPAA_Rating;
}

void Movie::setName(string name)
{
	this->name = name;
}

string Movie::getName()const
{
	return name;
}

void Movie::setMPAA_Rating(string MPAA_Rating)
{
	if (MPAA_Rating == "G" ||
		MPAA_Rating == "PG" ||
		MPAA_Rating == "PG-13" ||
		MPAA_Rating == "R")
		this->MPAA_Rating = MPAA_Rating;
	else
		this->MPAA_Rating = "UNRATED";
}

string Movie::getMPAA_Rating()const
{
	return MPAA_Rating;
}

void Movie::addRating(int r)
{
	if (r == 1)
		ratedTerrible = 0;
	else if (r == 2)
		ratedBad = 25;
	else if (r == 3)
		ratedOK = 50;
	else if (r == 4)
		ratedGood = 75;
	else if (r == 5)
		ratedGreat = 100;
	else
		return;
}

double Movie::getAverage()const
{
	double average = 0;

	return -1;
}

// <--- Added these prototypes.
char inputChar(string prompt, char yes, char no);
int inputInteger(string prompt, int startRange, int endRange);
string toUpper(string str);

int main()
{
	Movie movieRatings;
	string movieTitle, mpaaRating;

	cout << "\n Enter a movie title: ";
	std::getline(cin, movieTitle);  //<--- Changed.
	movieRatings.setName(movieTitle);

	cout << "\n Enter MPAA Rating (G || PG || PG-13 || R): ";
	std::getline(cin, mpaaRating);  //<--- Changed.
	movieRatings.setMPAA_Rating(toUpper(mpaaRating));

	char ans;
	
	do
	{
		int movieRating = inputInteger("\n Enter rating (1-Terrible, 2-Bad, 3-OK, 4-Good, 5-Great): ", 1, 5);
		movieRatings.addRating(movieRating);
		cout << "\n\n You rated " << movieTitle << " a " << movieRating << endl;

		ans = inputChar("\n\n Add another rating (Y/N)? ", 'y', 'n');

	} while (ans == 'y');


	//output  Changed the output.
	cout << "\n"
		<< std::setw(14) << "TITLE: " << movieRatings.getName() << '\n'
		<< std::setw(14) << "MPAA RATING: " << movieRatings.getMPAA_Rating() << '\n'
		<< std::setw(14) << "RATING: " << movieRatings.getAverage() << std::endl;

	return 0;
}

//just some validation function that you may want to move up before main if you wish to run the code...
char inputChar(string prompt, char yes, char no)
{
	char input;

	do
	{
		cout << prompt;
		if (!(cin >> input))
		{
			cout << "\n    ERROR-1A: Invalid input. Must be a character type.\n";
			cin.clear();
			std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');  // <--- Requires header file <limits>.
		}
		//else if (tolower(input) != tolower(yes) && tolower(input) != tolower(no))
		else if (tolower(input) != yes && tolower(input) != no)  // <--- Changed the condition.
			cout << "\n    ERROR-2A: Invalid input. Must be a '" << static_cast<char>(toupper(yes)) << "' or '" << static_cast<char>(toupper(no)) << "' character.\n";
		else
			break;
	} while (true);

	return input;
}

int inputInteger(string prompt, int startRange, int endRange)
{
	int input;

	do
	{
		cout << prompt;

		if (!(cin >> input))
		{
			cout << "\n    ERROR-3A: Invalid input. Must be an integer type.\n";
			cin.clear();
			std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');  // <--- Requires header file <limits>.
		}
		//else if (!(input >= min(startRange, endRange) && input <= max(startRange, endRange)))
		else if (!(input >= startRange && input <= endRange))  // <--- Changed the condition.
			cout << "\n    ERROR-3A: Invalid input. Must be from " << startRange << "..." << endRange << ".\n";
		else
			break;
	} while (true);

	return input;
}

string toUpper(string str)
{
	for (size_t i = 0; i < str.length(); i++)
	{
		str.at(i) = toupper(str.at(i));
	}

	return str;
}

The header file "<cctype>" is for "std::tolower()" and "std::toupper" along with some other useful functions. DO NOT count on your compiler and header files to include this at some point.

"<iomanip>" may be ahead of where you are at. If so the lines at the end of "main" that use "std::setw()" can be done by adding spaces to the "string".

At least give it a run and see what is displayed on the screen. You can change any part that you want.

In "main" your lines:
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cout << "\n Enter a movie title: ";
cin >> movieTitle);

And the next one for "mpaaRating" are a problem. This is formatted input which means it will stop at a space or new line (\n) whichever comes first.

What you would end up with, with a movie title like "Gone With the Wind". All would be placed in the input buffer and cin >> movieTitle; would get "Gone" and the space, which it discards, leaving the rest in the input buffer. The the line cin >> mpaaRating; would get "With" and the space leaving "the Wind" in the input buffer.

Your next "cin >>" is to a numeric variable an it will not wait for the user to input a number it will try to put the "t" into the numeric variable causing "cin" to fail and entering the "if" part in the function "inputInteger" to deal with the error. When it is finished you have reset the state bits on "cin" and cleared the input buffer, so everything is fine after that.

I would say the better choice to clear the input buffer is:
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // <--- Requires header file <limits>.

The do/while loop in "main" works, but not well. If ten people enter a rating for a movie how do you know how many times the loop has run. And if those ten people happen to enter the same rating how would you know how many people chose that rating?

As MikeyBoy pointed the addRating() function and the variables it uses do not have much use right now. Maybe later it will.

You said:
I’ve actually included those functions toward the end. moving them above main

Moving them was not necessary All you needed was to put the prototypes above "main":
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char inputChar(string prompt, char yes, char no);
int inputInteger(string prompt, int startRange, int endRange);
string toUpper(string str);

Usually I just copy the function definition and put that above "main" and add the semi-colon.

For the miner things: look closely at the above and see where I have added some blank lines. To the compiler this means nothing. To the reader it improves readability greatly.

After that there are some comments on things I have changed. The bold type should help find them.

Hope that helps,

Andy
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