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Get sequence of random n numbers that add up to something but only from a specific set of numbers

What I need is:
e.g:
Sum should be equal to:
120 (user input)
Number of numbers/items:
80 (user input)
Range of numbers to be used in set(from):
0 (user input)
Range of numbers to be used in set(to):
4 (user input)
Output:
1,1,3,2,1,1,0,0,1,1,2,1,0,2,3,3,1,2,0,0,0,1,3,2,3,1,0,0,2,3,2,3,2,2,1,1,0,0,2,0,1,0,1,1,3,3,1,3,1,0,0,3,2,1,0,0,2,1,2,3,0,3,1,1,3,3,2,2,1,1,3,1,3,3,3,3,3,1,2,0
These are all numbers that are between 0 and 4, their sum is 120 and are 80 in total.
What i've done is:
static void Main(string[] args)
{
bool loopOn = true;
Program p = new Program();
Console.WriteLine("____________________________________________________________________________");
Console.WriteLine("");
Console.WriteLine("Sum should be equal to:");
int sum = int.Parse(Console.ReadLine());
Console.WriteLine("Number of items:");
int items = int.Parse(Console.ReadLine());
Console.WriteLine("Range(from):");
int from = int.Parse(Console.ReadLine());
Console.WriteLine("Range(to):");
int to = int.Parse(Console.ReadLine());
while (loopOn == true)
{
List<int> number_list = p.createNumberSet(items, from, to);
if (number_list.Sum() == sum)
{
loopOn = false;
Console.WriteLine("____________________________________________________________________________");
Console.WriteLine("Start");
number_list.ForEach(Console.WriteLine);
Console.WriteLine("Stop");
Console.WriteLine("____________________________________________________________________________");
}
}
Console.WriteLine("Press any key to exit....");
Console.ReadLine();
}
public List<int> createNumberSet(int itemNumber, int range_from, int range_to)
{
List<int> number_set = new List<int>();
Random r = new Random();
for (int i = 0; itemNumber > i; i++)
{
number_set.Add(r.Next(range_from, range_to));
}
return number_set;
}
But this seems extremely in-efficent and doesn't seem to work with a lot of other examples. Does anyone have a better way of doing this?

Well, I am a bit lazy right now, so this is just an idea
Keep the first part:
bool loopOn = true;
Program p = new Program();
Console.WriteLine("____________________________________________________________________________");
Console.WriteLine("");
Console.WriteLine("Sum should be equal to:");
int sum = int.Parse(Console.ReadLine());
Console.WriteLine("Number of items:");
int items = int.Parse(Console.ReadLine());
Console.WriteLine("Range(from):");
int from = int.Parse(Console.ReadLine());
Console.WriteLine("Range(to):");
int to = int.Parse(Console.ReadLine());
Now, first of all, check is a solution exists:
if (from * items > sum) {
// There is no solution, handle accordingly
}
Let's focus on the interesting part now:
First create the list of necessary items
int[] number_set = new int[items];
for(int i = 0; i < items; i++) {
number_set[i] = from;
}
Find the difference between the wanted sum and the current sum of the list
int left_to_add = sum - from * items;
int idx = 0;
Random r = new Random();
while(left_to_add > 0) {
int toAdd = 0;
if (left_to_add < range_to - range_from) {
toAdd = r.Next(1, left_to_add);
} else {
toAdd = r.Next(1, range_to - range_from);
}
left_to_add -= toAdd;
number_set[idx] += toAdd;
idx++;
}
What's left to do is, convert the array to a list and shuffle it.
(I forgot that you actually can access list items by index, so there is no need to use an array as I did here)

At the algorithm level, this is what I would try:
Determine the number of each element, n[0], n[1], n[2], n[3] in your example (i.e. number of 0, number of 1 ...) and then generate a simple sequence by concatenating n[0] "0", n[1] "1", n[2] "2" and n[3] "3". Finally, a random sequence is obtained by performing a random permutation on this simple sequence.
The problem is therefore to determine the n[i].
The first step is to determine the average values of these n[i]. It your example, it is simple, as we can take average n_av[i]=20 for all index i.
In a more general case, we have to insure that
sum_i n_av[i]*i = sum_target (120 here) (1)
knowing that
sum_i (n[i]) = n = 80 here. (2)
In the general case, there is no necessary one unique good solution. I will try to propose an example of solution here if you provide an example of a difficult scenario.
The second step consists in selecting some random n[i] values around these average values. One possibility is to generate rounded Gaussian variables: we already know the averages, we just need to determine the variances. One possibility is to consider the variance that we will get if we were generating directly the random values, i.e. by considering the variance of the corresponding binomial variable :
var = n p(1-p). Here p[i] = n_av[i]/n
The last step consists in adjusting the values of the n[i] such that the sum of the n[i] is equal to the target. This is simply obtained by slightly increasing or decreasing some n[i] values.

For loop for calculating score, how to combine two methods

In my method public static int PointsCalculator() I seem to be unable to use my values from my two other methods in order to compare the values in the two array and give points.
I'm not really sure how to call or initialize the values to begin but tried to do a quick mockup.
My goal is to add one point for every user value in the GetUserGuesses method that is the same as the random values in the RandomBingoNumbers method.
class UserBingo // Creates a class to store all user related
{
static int[] RandomNrs;
static int[] userGuesses;
static int num = 0;
public static int[] GetUserGuess() // A method for collecting user guesses and displaying them (SPLIT THEM UP)
{
userGuesses = new int[10]; // Creates the array to store 10 user inputs
for (int i = 0; i < userGuesses.Length; i++) // For loop itterates until 10 user values are put into the array
{
try
{
int input = Convert.ToInt32(Console.ReadLine());
if (input < 1 || input > 25) // Only values between 1-25
{
Console.WriteLine("Only enter a number between 1-25");
i--;
}
else if (userGuesses.Contains(input)) // Checks for repeated values
{
Console.WriteLine("You have already entered {0}", input);
i--;
}
else
{
userGuesses[i] = input; //When they do meet the correct values
Console.WriteLine("Thanks for entering the number " + input);
}
}
catch (Exception)
{
Console.WriteLine("Only numbers can be entered, ");
i--;
}
}
for (int i = 0; i < userGuesses.Length; i++) // Loop to display all the input values in the array
{
Console.Write(userGuesses[i]);
}
return userGuesses;
}
public static int[] RandomBingoNumbers() // Method for creating 10 random integers
{
RandomNrs = new int[10]; // Creates an array to store 10 integer
Random rnd = new Random();
for (int i = 0; i < RandomNrs.Length; i++)
{
num = rnd.Next(1, 25);
if (RandomNrs.Contains(num))
i--;
else
RandomNrs[i] = num;
}
return RandomNrs;
}
public static int PointsCalculator() //Method for calculating score
{
int points = 0; // Integer to hold the amount of correct guesses
for (int i = 0; i < 10; i++)
{
if (RandomNrs[i] == userGuesses[i]) // Check if the 10 user inputs is the same as the 10 randomized numbers
{
points++;
}
}
Console.WriteLine("Your Numbers: \n [{0}]", string.Join(", ", userGuesses)); // Display user inputed numbers
Console.WriteLine("Bingo Numbers: \n [{0}]", string.Join(", ", RandomNrs)); // Display the random bingo numbers
Console.WriteLine("You got: " + points + "poäng"); // Display the amount of correct guesses
return points;
}
}
}

Add a using System.Linq;
Lot of mistakes.
if (GetUserGuess == RandomBingoNumbers
) // Check if the 10 user inputs is the same as the 10 randomized numbers
{
points++;
}
should be
if (GetUserGuess().SequenceEqual(RandomBingoNumbers())
// Check if the 10 user inputs is the same as the 10 randomized numbers
{
points++;
}
And so many other mistakes, like the RandomNrs must be a static int[] declared outside the function. etc. etc..
This assignment is wrong RandomNrs[i] = new UserBingoNrs;. I'd suggest you to go over the entire syntax and usage of functions.
UPDATE 1
Instead of this
int[] RandomNrs = new int[10]; // Creates an array to store 10 integer
int[] userGuesses = new int[10]; // Creates the array to store 10 user inputs
you should use
RandomNrs = new int[10]; // Creates an array to store 10 integer
userGuesses = new int[10]; // Creates the array to store 10 user inputs
because RandomNrs and userGuesses is already defined globally.
and instead of
RandomNrs == userGuesses and RandomNrs != userGuesses
you must use
RandomNrs[i] == userGuesses[i]) and RandomNrs[i]!=userGuesses[i]
else if (RandomNrs[i] != userGuesses[i]) // If user guesses are not equal to array points
i--;
This will probably cause an infinite loop, instead of i--, do points--;
UPDATE 2
As simple as this
int num= rnd.Next(1, 25);
while(RandomNrs.Contains(num))
num = rnd.Next(1,25);
UPDATE 3
Change your PointsCalculator for loop to this
for (int i = 0; i < 10; i++)
{
for (int j = 0; j < 10; j++)
if (RandomNrs[i] == userGuesses[j]) // Check if the 10 user inputs is the same as the 10 randomized numbers
{
points++;
}
}

Getting an average from a C# array

I have been working on this assignment for a couple days now. I have written all the code myself. I'm not looking to cheat or have someone do my work for me, but for the life of me, I can't get this to work correctly.
The problem I'm having is that when I try to average numbers in an array, instead of dividing by just the number of entries, it's dividing by the total allowed entries into the array.
For example. I enter 2 values into an array that can hold 100 values, instead of dividing by 2, it divides by 100.
How do I get it to divide by just the number of entries? Here is what I have:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication6
{
class Program
{
static void InputData(string[] player, int[] score, ref int numPlayer)
{
// input items up to the number of the array size
while (numPlayer < player.Length)
{
Console.Write("Enter player name (Q to quit): ");
player[numPlayer] = Console.ReadLine();
if ((player[numPlayer] == "Q") || (player[numPlayer] == "q"))
{
Console.WriteLine();
break;
}
else
{
Console.Write("Enter score for " + player[numPlayer] + ": ");
score[numPlayer] = Convert.ToInt32(Console.ReadLine());
numPlayer++;
}
}
}
static void DisplayPlayerData(string[] player, int[] score, int numPlayer)
{
Console.WriteLine("Name Score");
for (int i = 0; i < numPlayer; i++)
Console.WriteLine("{0, -16} {1, 8}", player[i], score[i]);
}
static double CalculateAverageScore(int[] score, ref int numPlayer)
{
double avgScore;
double total = 0;
for (int i = 0; i < numPlayer; i++)
{
total += score[i];
}
avgScore = total / score.Length;
Console.WriteLine("Average Score:" + avgScore);
return avgScore;
}
static void DisplayBelowAverage(string[] player, int[] score, int numPlayer)
{
double avgScore = CalculateAverageScore(score, ref numPlayer);
Console.WriteLine("Players who scored below average");
Console.WriteLine("Name Score");
for (int i = 0; i < numPlayer; i++)
{
if (score[i] < avgScore)
{
Console.WriteLine("{0, -16} {1}", player[i], score[i]);
}
}
}
static void Main(string[] args)
{
//Variables
string[] player = new string[100];
int[] score = new int[100];
int numPlayer = 0;
InputData(player, score, ref numPlayer);
DisplayPlayerData(player, score, numPlayer);
CalculateAverageScore(score, ref numPlayer);
DisplayBelowAverage(player, score, numPlayer);
Console.ReadLine();
}
}
}

You have a numPlayer variables that stands for a number of entered players.
Just use it.
Replace
avgScore = total / score.Length;
with
avgScore = total / numPlayer;
Your code has some very strange points.
For example, you call CalculateAverageScore(score, ref numPlayer); in a Main(). However, you are not using a return value. This method is properly called in a DisplayBelowAverage method.
In general, it looks wrong - refs, static-sized array with dynamic number of values, non-format console writeline etc.
Just for you information. Read this once. Maybe some code lines will help you. Maybe, you won't find something new, unknown or interesting.
This is how I would solve this problem:
public class Program
{
private const string InputTerminationString = "Q";
public static void Main()
{
List<Player> players = new List<Player>(); // p. 1, 4
while (true)
{
Console.Write("Enter player name ({0} to quit): ", InputTerminationString);
string name = Console.ReadLine();
if (name == InputTerminationString) break; // p. 2
Console.Write("Enter score for {0}: ", name); // p. 3
int score = int.Parse(Console.ReadLine());
players.Add(new Player { Name = name, Score = score });
}
Console.WriteLine("Name Score");
players.ForEach(x => Console.WriteLine("{0, -16} {1, 8}", x.Name, x.Score)); // p. 5
double average = players.Average(x => x.Score); // p. 6
Console.WriteLine("Average score: {0:F2}", average); // p. 3
Console.WriteLine("Players who scored below average");
Console.WriteLine("Name Score");
players
.Where(x => x.Score < average) // p. 7
.ToList()
.ForEach(x => Console.WriteLine("{0, -16} {1, 8}", x.Name, x.Score)); // p. 5
}
}
public class Player
{
public string Name { get; set; }
public int Score { get; set; }
}
Now, step by step:
Use Player class. It is pretty inconvenient to pass two independent arrays of names and scores. Moreover, it is not safe and proper in general. A name and a score of a player are properties if a single player and should be stored together either in struct or class.
Use constants. If you need to change 'Q' termination string to 'Exit', you will be able to do this in a second without looking through the code.
Use formatted Console.WriteLine. It works liks String.Format and you don't need to concatenate strings.
Some info here: https://msdn.microsoft.com/en-us/library/828t9b9h(v=vs.110).aspx
Use dynamic collection List. Array is good for storing and rapid accessing to range of values of known length. Since a user enters values one by one, you never know if he will enter 0, 1 or 90000 values. List collection will help you with it.
Some info here: http://www.dotnetperls.com/list
You can use ForEach method which executes the given code for every item in a collection. Using ForEach with lambda-expressions makes code shorter and more readable.
Some info here: https://msdn.microsoft.com/en-us/library/bwabdf9z(v=vs.110).aspx
Use Average function which calculates the average of a collection. In case of int[] you can use arr.Average(). However, in case of Class object, you need to describe the logic of calculation of average value using lambda-expression.
Some info here: http://www.dotnetperls.com/average
LINQ Where expression lets you filter your collection.
Some info here: http://www.dotnetperls.com/where

Instead of writing CalculateAverageScore the you can make use of LINQ's Average method:
double avgScore = score.Average();
Console.WriteLine("Average Score:" + avgScore);
Forthermore it is better not to mix calculating with I/O, so:
static double CalculateAverageScore(int[] score) {
return score.Average();
}
Or since you use an array, use the sum:
static double CalculateAverageScore(int[] score, ref int numPlayer) {
return (double) score.Sum()/numPlayer;
}
and do the printing in the Main:
static void Main(string[] args) {
//Variables
string[] player = new string[100];
int[] score = new int[100];
int numPlayer = 0;
InputData(player, score, ref numPlayer);
DisplayPlayerData(player, score, numPlayer);
double avgScore = CalculateAverageScore(score, ref numPlayer);
Console.WriteLine("Average Score:" + avgScore);
DisplayBelowAverage(player, score, numPlayer);
Console.ReadLine();
}
online Ideone demo.
You furthermore better modify the array to a List. Here there is also no reason to use the ref keyword in all these methods, nor to make them static.

taking specific info out of an array

Below is the code I have written. What I'm trying to do is say enter 3 players names and the number of goals they have scored. Then the application should output the players name with the most goals and his number of goals. Also the application should output the lowest number of goals scored and the average goals scored. I can get the max goals scored but I cant figure out how to link the players name to goals scored. Also when I try and get the lowest goals scored I keep getting a value of 0. Thanks for the help.
{
string []player = new string[20];
double [] goalsScored = new double[20];
int numberOfPlayers;
Console.WriteLine("Enter the number of players:");
numberOfPlayers = int.Parse(Console.ReadLine());
for (int i = 0; i < numberOfPlayers; i++)
{
Console.WriteLine("Enter a players name:");
player[i]= Console.ReadLine();
Console.WriteLine("Goals scored so far this season");
goalsScored [i] = int.Parse(Console.ReadLine());
}
double max = goalsScored.Max();
double sum = goalsScored.Sum();
double average = sum / numberOfPlayers;
Console.WriteLine("Top player is: {0} with {1} goals", player, max);
Console.WriteLine("The average goals scored was:{0}",average);
double min = goalsScored.Min();
Console.WriteLine("The lowest goals scored was: {0}", min);
Console.ReadLine();
}
}
}

You should get the number of players first, then create your arrays using that number.
For example:
string[] player = new string[numberOfPlayers];
This may explain why you're always getting zero as the minimum score. If your array contains empty spots (if you entered less than 20 players/scores).
To "link" the player's name with his goals scored, you should really use a Player class so you can just have a single array of Player objects and use it for both scores and names. Then you'd end up with something like:
Console.WriteLine("Top player is: {0} with {1} goals", topPlayer.name, topPlayer.score);

You can't do this easily using arrays. You could use a Dictionary, which would allow you to look up a player's name and get the goals out. Indeed this sort of pairing of values is kind of what dictionaries are for:
//declare a dictionary string, int. The "string" is the name which we look up to get the
//second data point of "int", which will be the number of goals
Dictionary<string, int> playerGoals = new Dictionary<string, int>();
//add a couple of players, and their goal tally
playerGoals.Add("Gianfranco Zola", 44);
playerGoals.Add("Wayne Rooney", 77);
//use the string name to retrieve the int value
int rooneyGoals = playerGoals["Wayne Rooney"];
//rooneyGoals is now 77
Quicky whipped through your original code - something like this should work:
Dictionary<string, int> playerGoals = new Dictionarty<string, int>()'
int numberOfPlayers;
Console.WriteLine("Enter the number of players:");
numberOfPlayers = int.Parse(Console.ReadLine());
for (int i = 0; i < numberOfPlayers; i++)
{
Console.WriteLine("Enter a players name:");
string playerName = Console.ReadLine();
Console.WriteLine("Goals scored so far this season");
int goalsScored = int.Parse(Console.ReadLine());
playerGoals.Add(playerName, goalsScored);
}
double max = playerGoals.Values.Max();
double sum = playerGoals.Values.Sum();
double average = sum / numberOfPlayers;
Console.WriteLine("Top player is: {0} with {1} goals", player, max);
Console.WriteLine("The average goals scored was:{0}",average);
double min = playerGoals.Values.Min();
Console.WriteLine("The lowest goals scored was: {0}", min);
Console.ReadLine();

Linq solution :)
var players = player.Zip(goalsScored, (n,g) => new { Name = n, Goals = g });
var topGoalscorer = players.OrderByDescending(p => p.Goals).First();
var misser = players.OrderBy(p => p.Goals).First();
topGoalscorer.Goals // max goals
topGoalscorer.Name // player name
Using goals value:
string playerName = player[Array.IndexOf(goalsScored, min)];
Alternative solution:
int maxScoredGoals = -1;
string topGoalscorer = "";
for(int i = 0; i < numberOfPlayes; i++)
{
if (goalsScored[i] <= maxScoredGoals)
continue;
maxScoredGoals = goalsScored[i];
topGoalsocrer = player[i];
}
Suggestions: use single data structure to hold related data, i.e. player name and scored goals
public class Player
{
public string Name { get; set; }
public int Goals { get; set; }
}
Also use generic collection instead of arrays:
List<Player> players = new List<Player>();
Filling collection:
for(int i = 0; i < numberOfPlayers; i++)
{
var player = new Player();
player.Name = Console.ReadLine();
player.Goals = Int32.Parse(Console.ReadLine());
players.Add(player);
}
Getting top goalscorer:
var topGoalscorer = players.OrderByDescending(p => p.Goals).First().Name;
Or with MoreLINQ:
var topGoalscorer = players.MaxBy(p => p.Goals).Name;

You can use indirect sorting using Array.Sort(goalsScored, players); to keep a second array in sync while sorting an array. Other issues are addressed in the comments in the following code.
var numberOfPlayers = Int32.Parse(Console.ReadLine());
// Allocate the arrays with the correct size; in your code numberOfPlayers
// larger than 20 will cause trouble.
var players = new String[numberOfPlayers];
var goalsScored = new Double[numberOfPlayers];
// Fill the arrays as in your code.
// This will sort the goalsScored array and simultaneously
// bring the players array into the same order; that is called
// indirect sorting.
Array.Sort(goalsScored, players);
// The maximum number of goals scored and the associated player
// are now in the last array position.
var topPlayer = players.Last();
var maxNumberGoals = goalsScored.Last();
// You always got 0 because you always allocated arrays of size
// 20 and if you have less than 20 players all the superfluous
// entries in the array just have their default value of 0 making
// the minimum in the array 0.
var minNumberGoals = goalsScored.First();
var totalNumberGoals = goalsScored.Sum();
var averageNumberGoals = goalsScored.Average();
Unfortunately there is only out of the box support for this with arrays while it might be better to use lists and just add new players and scores until the users says that there are no more players to be entered instead of forcing the user to enter the number of players in advance.
Other answer suggest to use a more object oriented design and combine players and scored goals into a class or at least use a dictionary and I really suggest the same but I won't bother duplicating answers already here.

C# - displaying the max, min, and average

I am new to C#. I have been working on this program and researching but am not getting anywhere. The goal is to have the user enter numbers (how many is up to the user). when they enter a 0, it will stop the program and display the minimum number entered, the maximum number entered, and the average of all numbers entered. I am not getting any errors and I am getting. If someone can please point me in the right direction.
The WriteLines are returning:
Lowest number is 0
Highest number is 0
Average is: 0
Count: 5
Here is my code:
int LOWEST =0;
int HIGHEST=0;
const int STOP = 0;
double average = 0;
int input;
int count = 0;
Console.WriteLine("Enter a number. You can end the program at anytime by entering 0");
input = Convert.ToInt32(Console.ReadLine());
while (input != STOP)
{
for (int i=0; input != STOP; i++)
{
Console.WriteLine("Enter a number. You can end the program at anytime by entering 0");
input = Convert.ToInt32(Console.ReadLine());
count++;
var Out = new int[] { input };
LOWEST = Out.Min();
HIGHEST = Out.Max();
average = Out.Average();
if ((input > LOWEST) || (input < HIGHEST))
{
LOWEST = Out.Min();
}
if (input > HIGHEST)
{
HIGHEST = Out.Max();
}
}
}
Console.WriteLine("Lowest number is {0}", LOWEST);
Console.WriteLine("Highest number is {0}", HIGHEST);
Console.WriteLine("Average is {0}", average);
Console.WriteLine("Count: {0}", count);
Console.ReadLine();

On each run you are constructing a new array of integers:
var Out = new int[] { input };
After this line, Out contains one item: the last input. Calling Min, Max and Average on it will return the last value. Which is zero if you ended the program.
instead of creating a new array each time, you want to create a List<int> at the beginning of your program and then add each input to it. You can then use the whole list of values to calculate Min, Max and Average.
Eventually you can change your code into something like this:
const int STOP = 0;
int input = -1;
List<int> Out = new List<int>();
while (input != STOP)
{
Console.WriteLine("Enter a number. You can end the program at anytime by entering 0");
input = Convert.ToInt32(Console.ReadLine());
if (input == STOP) break;
Out.Add(input);
}
Console.WriteLine("Lowest number is {0}", Out.Min());
Console.WriteLine("Highest number is {0}", Out.Max());
Console.WriteLine("Average is {0}", Out.Average());
Console.WriteLine("Count: {0}", Out.Count);
Console.ReadLine();

List<int> numbers = new List<int>();
numbers.Add(10);
numbers.Add(30);
numbers.Add(20);
numbers.Add(0);
numbers.Max();
numbers.Min();
numbers.Average();
returns 30, 0 and 15.

Before your loop, you should probably make Out an extensible data structure analogous to an array, the List.
List<int> Out = new List<int>();
then each loop, you can
Out.Add(input);
Since this sounds like an exercise for the reader, you can then traverse your list and compute the average from all data values.
Alternately, before the loop, you could declare
int n = 0;
int total = 0;
and each loop, do
n += 1;
total += input;
From these, you should be easily able to compute the average.