Trouble Implementing Two Vectors MVS C++ - c++

Question

Hello Stack Overflow users,
I have this program that i am trying to create for my collection of movies, and please forgive me for some of my mistakes and oversights since I AM NEW TO C++, but basically my program runs (yay) but when I chose any of the four options this error pops up:
Main Error
I want the first program option to display like this:
Akira 10.0
Blade Runner 10.0
Deadpool 8.8
BUT IT DOESN'T DO THAT it just looks like:
10.0
10.0
8.8
Example of my bad output
My output just displays all of the scores on new lines but no movie titles show up and if I try any of the last three options (highest/lowest/average) it just displays the same error: Same error as above
If you could give me any pointers (or a code example) as what I need to do to make the output appear as the bold one above, that would be amazing!
Again please forgive me for possible simple errors I am making since this is my first time working with vectors.
#include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <cmath>
#include <cstdlib>
using namespace std;
// Function Prototypes
void displayList(vector<string>,vector<double>);
void highestRating(vector<double>);
void lowestRating(vector<double>);
void averageRating(vector<double>);
// 1st Vector Defintion
vector<string> movies{ // inside this is a list of 48 strings containing movie names (Ex: "Akira", "Blade Runner" };
// 2nd Vector Definition
vector<double> ratings{ // Inside this is a list of 48 doubles that contain movie scores for each movie
and i wish for it to print out directly right of the movie title, then turn to the next line.
Examples of numbers inside this vector: 9.9, 10.0, 5.5, 7.5 };
// Main
int main()
{
cout << fixed << showpoint << setprecision(1);
// Variable Definitions
const int DISPLAY = 1, HIGHEST = 2, LOWEST = 3, AVG = 4;
int response;
cout << "-------Welcome to C++ Newbie's Movie Collection Database-------" << endl;
cout << "\nEnter 1 to display the whole collection" << "\nEnter 2 to display the 5 highest rated movies by me";
cout << "\nEnter 3 to display the lowest 5 rated movies by me" << "\nEnter 4 to display the average score of the movies in the collection along with some other math" << endl;
cin >> response;
// Menu
do
{
switch (response)
{
case(DISPLAY):
{
displayList(movies, ratings);
break;
}
case(HIGHEST):
{
highestRating(ratings);
break;
}
case(LOWEST):
{
lowestRating(ratings);
break;
}
case(AVG):
{
averageRating(ratings);
break;
}
default:
{
exit(0);
}
}
} while (response == 1 || response == 2 || response == 3 || response == 4);
return 0;
}
// Display List
void displayList(vector <string> movies, vector <double> ratings)
{
for (int val = 0; val <= movies.size(); ++val)
{
cout << movies[val] << "\t";
for (int rat = 0; rat <= ratings.size(); ++rat)
{
cout << ratings[rat] << endl;
}
}
}
// Display highest by me
void highestRating(vector<double> ratings)
{
double max = ratings[0];
for (int i = 0; i <= ratings.size(); i++)
{
if (ratings[i] >= max)
max = ratings[i];
}
cout << "\nThe highest rated movie is " << max << endl;
}
// Display Lowest by me
void lowestRating(vector<double> ratings)
{
double min = ratings[0];
for (int a = 0; a <= ratings.size(); a++)
{
if (ratings[a] <= min)
min = ratings[a];
}
cout << "\nThe lowest rated movie is" << min << endl;
}
// Average Score by me
void averageRating(vector<double> ratings)
{
double average;
double total = 0;
for (int x = 0; x <= ratings.size(); x++)
{
total += ratings[x];
}
average = total / ratings.size();
cout << "\nThe average is " << average << endl;
double forTheFunOfIt = fmod(average, 2.0);
cout << "\nThe Average divided by 2 is " << forTheFunOfIt << endl;
}

Answer 1

To address your first problem in displayList(), you are displaying a movie, and then looping to display all of the ratings. You probably need to display both within the same single loop. Also, if you do this then you need to make sure that both vectors have the exact same sizes to avoid attempting to access beyond the range of your vector, (it is probably best to use a std::map of movies and rating).
Having said that, for your code above maybe try changing displayList() to something like
// Display List
void displayList(vector <string> movies, vector <double> ratings)
{
for (int val = 0; val < movies.size(); val++)
{
cout << movies[val] << "\t" << ratings[val] << std::endl;
}
}
Note, you are not going to want to loop while val <= movies.size(), the indexes to your vector of (for example) 4 movies and 4 ratings will be 0-3, not 0-4. You will encounter an error indicating you are out of range.
Now for your next problem, you are looping in main() on the initial input from the user, but you are never updating the response variable from a user input. This will cause you to fall into an infinite loop! An easy fix for you will be to move cin >> response into the top of your do-while loop.
Moving onto the next couple issues, which is invalid output for your highest, lowest, and average. Again, you should not be looping while the index is less than or equal to the total size of the vector. Instead, you want less than only.
Lastly, you may want to consider passing your vectors as const references