I have a class called Recipe. The Recipe maynot contain duplicate Ingredients, otherwise a Illegal Argument Exception should be thrown. I tried to use a helplist but I am getting a NullPointerException for the line: "for (int i = 0; i < ingredients.size(); i++)"
public class Recipe {
private String title;
private String instructions;
private LinkedList<Ingredient> ingredients;
boolean noduplicate = true;
// constructor
public Recipe(String title, String instructions,
List<Ingredient> ingredients) {
this.title = title;
this.instructions = instructions;
LinkedList<Ingredient> helplist = new LinkedList<Ingredient>();
for (int i = 0; i < ingredients.size(); i++) {
Ingredient x = ingredients.get(i);
if (helplist.contains(x)) {
noduplicate = false;
throw new IllegalArgumentException(
"This ingredient is duplicate!");
}
if (noduplicate) {
helplist.add(x);
}
noduplicate = true;
}
this.ingredients = helplist;
}
}
Use a set instead of a list, since that is the datastructure you want. In short, a set only contains unique elements. When you try to add stuff which is already there, nothing happens. You have to override the equal/hash method of your Ingredients class in order to make it work.
http://docs.oracle.com/javase/7/docs/api/java/util/Set.html
http://docs.oracle.com/javase/7/docs/api/java/util/HashSet.html
Related
I im currently having an issue with when performing an operation with my structure.
On form load, I am loading a comma delimited file with 6 indexes then using a 2d array i display the structured list's field to a grid view cell.
In the last for loop, perform the operation using my total field?
{
public partial class Form1 : Form
{
public struct Costomers
{
public string firstN;
public string lastN;
public string address;
public string item;
public double price;
public int quantity;
public double total;
}
public Form1()
{
InitializeComponent();
}
List<Costomers> consumers = new List<Costomers>();
private void Form1_Load(object sender, EventArgs e)
{
var inputfile = File.ReadAllLines("customers.txt");
for (int i = 0; i < inputfile.Length; i++)
{
var SplitArr = inputfile[i].Split(',');
// next declare a new instace of costomers
Costomers ConsumerInfo = new Costomers();
// the ConsumerInfo object now contains all of the fields i declared in the structer.
// next i want to access the Objects fields and assign them
ConsumerInfo.firstN = SplitArr[0];
ConsumerInfo.lastN = SplitArr[1];
ConsumerInfo.address = SplitArr[2];
ConsumerInfo.item = SplitArr[3];
ConsumerInfo.price = Convert.ToDouble(SplitArr[4]);
ConsumerInfo.quantity = Convert.ToInt32(SplitArr[5]);
//ConsumerInfo.total = consumers[i].price * consumers[i].quantity;
consumers.Add(ConsumerInfo);
}
// Next i need to disply each field in the grid view
// i will resue my code from section F to do this.
for (int i = 0; i < consumers.Count; i++)
{
dgInfo.Rows.Add();
dgInfo[0, i].Value = consumers[i].firstN;
dgInfo[1, i].Value = consumers[i].lastN;
dgInfo[2, i].Value = consumers[i].address;
dgInfo[3, i].Value = consumers[i].item;
dgInfo[4, i].Value = consumers[i].price;
dgInfo[5, i].Value = consumers[i].quantity;
}
// next in a seperat for loop i need too mutiply the price by the quantity
for (int i = 0; i < consumers.Count; i++)
{
Costomers totalPrice = new Costomers();
totalPrice.total = consumers[i].price * consumers[i].quantity;
dgInfo[6,i].Value = totalPrice.total;
}
}
}
}```
Second, because the file i load does not contain a index for total; how to i display the total in its own column?
Text file as shown below:
The, Batman, 123 Gotham Drive, bat belt, 193.82,17
The, Joker, 12432 Joker Way, Bat Spray, 19.99, 1022
Cat, Women, 8787 Meow St., Kibbles, 9.99, 4700
The, Penguin, 17 Waddel Ave., pointy cigarettes, 24.99, 51700
sidekick, Robin, 123 Gotham Drive, junior bat belt, 67.80, 10000
Adam, West, 1782 Hollywood Dr., hasbeen kit, 10305018.18, 1
I have a list of objects of the same class.
This class contains an attribute I want to use.
I would like to get a list of all these attributes in one line. Is this possible?
Here is a small example: I just want a list of all the colors.
It is important that I return directly a list of these attributes, without the normal forEach statement.
void main() {
List<Car> listOfCars = [
Car('blue'),
Car('green'),
Car('yellow'),
];
}
//List<String> listOfColors = listOfCars[all].color;
class Car{
String color;
Car(this.color);
}
You can use the map function to achieve this
List<String> listOfColors = listOfCars.map((car) => car.color).toList();
print(listOfColors);
Just check out this code below:
void main() {
List<Car> listOfCars = [
Car('blue'),
Car('green'),
Car('yellow'),
];
List<String> stringList = List();
// This is where you get the single car object and then you add it the list of string
for (int i = 0; i < listOfCars.length; i++) {
stringList.add(listOfCars[i].color);
}
// this is the desired out put i have just printed your list :
print('This is the string length : ' + stringList.length.toString());
for (int i = 0; i < stringList.length; i++) {
print('This is the string list :' + stringList[i]);
}
}
class Car {
final String color;
Car(this.color);
}
Blow is the output :
This is the string length : 3
This is the string list :blue
This is the string list :green
This is the string list :yellow
I am making a Unity game where the player is collecting data about aliens.
Therefor the player points on the alien and uses something like a camera.
Camera --> shoots Ray --> Ray returns all needed data attached to the script on the alien-gameobject
void ShootRay()
{
RaycastHit hitInfo; // stores information about hitted object
if (Physics.Raycast (transform.position, transform.forward, out hitInfo, maxRaycastRange, 1 << LayerMask.NameToLayer("creature"))) // out hitInfo = Unity puts information in the variable hitInfo
{
// UI alerts and collecting dna
if (hitInfo.distance <= photoRaycastRange)
{
distanceInfo.text = "scanning_genome";
if (hitInfo.collider.gameObject.GetComponent<EnemyAI> ().dna_collected == false) {
if (dna_percent_0_to_1 < 1)
{
calming_dna_scan_circle = false;
distanceInfo.text = "scanning_genome";
dna_percent_0_to_1 += Time.deltaTime * dna_scanSpeed;
dna_collect_circle.fillAmount = dna_percent_0_to_1;
}
else if (dna_percent_0_to_1 >= 1)
{
// adding info of creature to database
if (hitInfo.collider.gameObject.GetComponent<EnemyAI> ().raceIndex == 1)
{
if (!raceOneWasAdded)
{
BestiariumData.scannedSpecies.Add (hitInfo.collider.gameObject);
raceOneWasAdded = true;
}
BestiariumData.dnaBar_1 += 0.25f;
The mentioned database is simply a class called BestiariumData with:
public static List<GameObject> scannedSpecies = new List<GameObject> ();
public static List<float> savedDNAFillRates = new List<float> ();
public static float dnaBar_1 = 0;
public static float dnaBar_2 = 0;
public static float dnaBar_3 = 0;
public static float dnaBar_4 = 0;
public static float dnaBar_5 = 0;
public static float dnaBar_6 = 0;
public static float dnaBar_7 = 0;
public static float dnaBar_8 = 0;
}
I'm having a menu where the player can check which aliens he/she already has collected data. The name of the alien is displayed (Monster One, ...) and a progress bar for how many alien individuals the player has scanned.
THE PROBLEM:
if I try to assign the NAME of the status bar if throws the ArgumentOutOfRangeException: Argument is out of range. Parameter name: index exception. I am doing this by setting a bool in another script to true.
public List<GameObject> monsterButtons = new List<GameObject>();
public static bool nameButtons = false;
// Update is called once per frame
void LateUpdate ()
{
if (nameButtons)
{
for (int buttonIndex = monsterButtons.Count; buttonIndex > 0; buttonIndex--)
{
monsterButtons [buttonIndex].GetComponentInChildren<Text> ().text = BestiariumData.scannedSpecies [buttonIndex].name;
}
}
}
Thank you for your help.
Button index gives the count of your list. So say your list contains 10 items, count will be 10.
However a list's index starts at 0, not 1.
So when you try to access monsterButtons [buttonIndex] for the first time, you are calling index 10, which means item 11. This does not exist so throws your error.
To fix, add "-1" to your index asigning:
for (int buttonIndex = monsterButtons.Count -1; buttonIndex >= 0; buttonIndex--)
{
monsterButtons [buttonIndex].GetComponentInChildren<Text> ().text = BestiariumData.scannedSpecies [buttonIndex].name;
}
I have the following for loop, in this foor loop I create an object kw.
The class keywords (string, vector<pair<int,string>>, vector<string>)
for(size_t i = 0; i < names.size();i++)
{
Keywords kw (names[i].c_str(),vreg, stopWords);
Document d = kw.extractKeywords();
v_doc.push_back(d);
}
I think that there is a problem in this for loop. I thought that it might be better if i take the Keywords out of the for loop, since i just need to create that object once.
Keywords kw (vreg, stopWords);
for(size_t i = 0; i < names.size();i++)
{
Document d = kw.extractKeywords(names[i].c_str());
v_doc.push_back(d);
}
When I do that I don't get the right output. Can you please give me a hint thank you.
Hani.
This class is being used to extract keywords out of an xml File. I provided the:
Class constructor
Copy Constructor
Setters and getters
Destructors
Do you think that there is a problem in the copy constructor
Keywords::Keywords(string xmlF,vector<pair<int, string>> re,vector<string> sw)
{
// Setter for string: the path of the xml File
setXml(xmlF);
// Setter for the vector<pair<int, string>> re
setRegularExpression(re);
//setter for vector<string> sw
setStopWords(sw);
}
//FREE MEMORY
Keywords::~Keywords()
{
sw.clear();
vreg.clear();
}
void Keywords::setRegularExpression(vector<pair<int, string>> re)
{
vreg = re;
}
vector<pair<int, string>> Keywords::getRegularExpression()
{
return vreg;
}
void Keywords::setStopWords(vector<string> s)
{
sw = s;
}
vector<string> Keywords::getStopWords()
{
return sw;
}
void Keywords::setXml(string xmlF)
{
xmlFile = xmlF;
}
///COPY CONSTRUCTOR
Keywords::Keywords(const Keywords& other):vreg(other.vreg),sw(other.sw)
{
}
kw is allocated in the second code only once, but in the first code for each loop iteration
In non runtime critical code it is good practice to construct objects in a RAII fashion.
I have a memory issue with a class of mine. The issue occurs when I create an object in a member function of a class. It is about the class below. I removed the member functions because they aren’t necessary:
class User
{
private:
bool locked;
bool active;
std::vector<City> * userCitys;
UserData userData;
Credentials credentials;
The problem occurs when I call this function:
int User::addCity(CityData cityData)
{
lockUserObject(); //Everything is fine here
City cityToAdd; //When this object is created, the memory of userCitys will get overridden
cityToAdd.activate();
userCitys->push_back(cityToAdd);
int cityID = userCitys->size() - 1;
userCitys->at(cityID).editCityData(cityData);
unlockUserObject();
return cityID;
}
In the first place I created userCitys on the stack. For test purpose I placed it on the Heap. The address of userCitys get overridden by some data. I can’t find the problem. the City is just a basic class:
Part of the header:
class City
{
private:
bool active;
Supplies supplies;
std::vector<Building> buildings;
std::vector<Company> companies;
std::vector<Share> shares;
std::vector<Troop> troops;
CityData cityData;
Constructor:
City::City()
{
active = false;
}
How is it possible that userCitys get overridden? This all happens on a single Thread so that can’t be a problem. I tried a lot of thing, but I can’t get it to work. What is the best approach to find the problem?
Edit:
Lock function:
void User::lockUserObject()
{
for( int i = 0; locked ; i++)
{
crossSleep(Settings::userLockSleepInterval);
if( i >= Settings::userLockMaxTimes )
Error::addError("User lock is over userLockMaxTimes",2);
}
locked = true;
}
I call the code here (Test function):
City * addCity(User * user)
{
Location location;
location.x = 0;
location.y = 1;
CityData citydata;
citydata.location = location;
citydata.villagers = 0;
citydata.cityName = "test city";
int cityID = user->addCity(citydata); //addCity is called here
City * city = user->cityAction(cityID);;
if( city == NULL)
Error::addError("Could not create a city",2);
return city;
}
The add user (Test code):
User * addUser()
{
UserData test;
test.name = "testtest";
Credentials testc("testtest",3);
//Create object user
int userID = UserControle::addUser(test,testc);
User * user = UserControle::UserAction(userID);
if( user == NULL)
Error::addError("Could not create a user",2);
return user;
}
My test function:
void testCode()
{
User * user = addUser();
City * city = addCity(user);
}
This function in called in main:
int main()
{
testCode();
return 0;
}
Here are UserAction and addUser in UserControle:
int UserControle::addUser(UserData userdata, Credentials credentials)
{
int insertID = -1;
for( int i = 0; i < (int)UserControle::users.size(); i++)
{
if( !UserControle::users.at(i).isActive() )
{
insertID = i;
break;
}
}
User userToInsert(userdata,credentials);
if( insertID != -1 )
{
UserControle::users.insert( UserControle::users.begin() + insertID,userToInsert);
return insertID;
}
else
{
UserControle::users.push_back(userToInsert);
return UserControle::users.size() - 1;
}
}
User* UserControle::UserAction(int userID) //check all indexes if greater then 0!
{
if( (int)UserControle::users.size() <= userID )
{
Error::addError("UserAction is out of range",3);
return NULL;
}
if( !UserControle::users.at(userID).isActive())
{
Error::addError("UserAction, the user is not active.",3);
return NULL;
}
return &UserControle::users[userID];
}
There's a few things you could try:
Remove code until the fault goes away. In other words, distill a minimal example from your code. I guess you'll then see the error yourself, otherwise post that small example program here and others will.
Don't use raw pointers. The question with those is always who owns what they point to. Use smart pointers instead, e.g. unique_ptr (C++11) or auto_ptr (C++98) for exclusive ownership.
If you have pointer members like "userCities", you need to think about what happens when copying instances of that class (you already wrote a proper destructor, or?). So, either prevent copying (make copy-constructor and assignment operator private and without implementing it) or implement them in a way that the vectors are properly cloned and not shared between different instances.
Don't use C-style casts. If those are necessary to get anything through the compiler, the code is probably broken.