Homework SourseCreate a program to store and process movie ratings Use a 2D
Create a program to store and process movie ratings. Use a 2D array to store ratings by different reviewers for different movies. Each row represents a different movie and each column represents a different reviewer. There will also be two separate arrays to store the names of movies and the names of the reviewers.
MovieRatings()
Constructor for the class
One parameter is an array of reviewers names
One parameter is an array of movie names
Description: set the parameters equal to the private data members for the movies and reviewers; initialize the 2D ratings array based on the size of the reviewers array (rows) and the size of the movies array (columns)
getAvgRating()
Returns a double value representing the average rating
Description: Find the average rating for all movies and all reviewers (i.e. all data in the table)
getAvgRatingsbyMovie()
One parameter, the index of the movie to find all the reviews for
Returns a double value representing the average rating
Description: Find the average rating for a single movie (i.e. one column representing all the reviewers scores for that one movie)
getAvgRatingsbyReviewer()
One parameter, the index of the reviewer to find all the reviews for
Returns a double value representing the average rating
Description: Find the average rating for a single reviewer (i.e. one row representing all the movies for that one reviewer)
getMovieIndex()
One parameter, the name of the movie
Returns an integer representing the index number of that movie
Description: Searches the movies array to find the index location for that movie. This can then be used to find the ratings for that movie in the ratings 2D array
getReviewerIndex()
One parameter, the name of the reviewer
Returns an integer representing the index number of that reviewer
Description: Searches the reviewers array to find the index location for that reviewer. This can then be used to find the ratings for that reviewer in the ratings 2D array
setRating()
One parameter each for the movie index, for the reviewer index and for the rating to store
Description: the reviewer index specifies the row, the movie index specifies the column and the rating is the value to store in that cell
printMovieRatings()
One parameter that represents the index of the movie name and the movie ratings
Description: prints the movie name and the ratings to System.out
Example: \"The Lego Movie: 5, 6, 2, 7, 8\"
printReviewerRatings()
One parameter that represents the index of the reviewers name and their movie ratings
Description: prints the reviewer name and the ratings to System.out
Example: \"Roger Ebert: 4, 2, 8, 9\"
Solution
package movie;
public class MovieRatings {
private String[] reviewers;
private String[] movies;
private double[][] ratings;
public MovieRatings(String[] reviewers, String[] movies) {
this.reviewers = reviewers;
this.movies = movies;
ratings = new double[reviewers.length][movies.length];
}
public double getAvgRating(){
double total = 0;
for(int i=0;i<ratings.length;i++){
for(int j=0;j<ratings[i].length;j++){
total = total+ratings[i][j];
}
}
return total/(reviewers.length*movies.length);
}
public double getAvgRatingsbyMovie(int index){
double total = 0;
if(index<=0 || index>movies.length){
System.out.println(\"Invalid Input\");
}
else{
for(int i=0;i<reviewers.length;i++){
total =total+ratings[i][index-1];
}
}
return total/reviewers.length;
}
public double getAvgRatingsbyReviewer(int index){
double total = 0;
if(index<=0 || index>reviewers.length){
System.out.println(\"Invalid Input\");
}
else{
for(int i=0;i<movies.length;i++){
total =total+ratings[index-1][i];
}
}
return total/movies.length;
}
public int getMovieIndex(String movieName){
for(int i=0;i<movies.length;i++){
if(movieName.equalsIgnoreCase(movies[i])){
return i+1;
}
}
return 0;
}
public int getReviewerIndex(String reviewerName){
for(int i=0;i<reviewers.length;i++){
if(reviewerName.equalsIgnoreCase(reviewers[i])){
return i+1;
}
}
return 0;
}
public void setRating(int movieIndex, int reviewerIndex, double rating){
ratings[reviewerIndex-1][movieIndex-1] = rating;
}
public void printMovieRatings(int movieIndex){
System.out.print(\"\ \"+movies[movieIndex-1]+\": \");
for(int i=0;i<reviewers.length;i++){
System.out.print(ratings[i][movieIndex-1]+\", \");
}
}
public void printReviewerRatings(int reviewerIndex){
System.out.print(\"\ \"+reviewers[reviewerIndex-1]+\": \");
for(int i=0;i<movies.length;i++){
System.out.print(ratings[reviewerIndex-1][i]+\", \");
}
}
/*public void printAll(){
for(int i=0;i<reviewers.length;i++){
for(int j=0;j<movies.length;j++){
System.out.print(ratings[i][j]);
}
System.out.println();
}
}*/
public static void main(String[] args) {
String[] reviewers = {\"a\",\"b\",\"c\"};
String[] movies = {\"movie-P\",\"movie-Q\"};
MovieRatings mr = new MovieRatings(reviewers,movies);
mr.setRating(mr.getMovieIndex(\"movie-P\"), mr.getReviewerIndex(\"a\"), 2);
mr.setRating(mr.getMovieIndex(\"movie-P\"), mr.getReviewerIndex(\"b\"), 3);
mr.setRating(mr.getMovieIndex(\"movie-P\"), mr.getReviewerIndex(\"c\"), 5);
mr.setRating(mr.getMovieIndex(\"movie-Q\"), mr.getReviewerIndex(\"a\"), 3);
mr.setRating(mr.getMovieIndex(\"movie-Q\"), mr.getReviewerIndex(\"b\"), 4.0);
mr.setRating(mr.getMovieIndex(\"movie-Q\"), mr.getReviewerIndex(\"c\"), 2);
//mr.printAll();
System.out.println(\"movie-Q avg raitngs: \"+mr.getAvgRatingsbyMovie(mr.getMovieIndex(\"movie-Q\")));
System.out.println(\"Reviewwer b ratings :\"+mr.getAvgRatingsbyReviewer(mr.getReviewerIndex(\"b\")));
mr.printMovieRatings(mr.getMovieIndex(\"movie-P\"));
mr.printReviewerRatings(mr.getReviewerIndex(\"a\"));
}
}
Output:
movie-Q avg raitngs: 3.0
Reviewwer b ratings : 3.5
movie-P: 2.0, 3.0, 5.0,
a: 2.0, 3.0,
