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Calculate average grades, excluding the entered values that are the lowest and greatest

The task is to allow the user to enter values between 0 and 100. If the user enters -99 the program should stop. Once the program has exited, the average must be computed. However, the average should include all the entered values, except the lowest value entered (minimum) and the greatest value entered (maximum). I have written a fairly good-looking code, but it throws an IndexOutOfRangeException.
Here is that code:
class Program
{
static void Main(string[] args)
{
DisplayApp();
Calculate();
}
static void DisplayApp()
{
Console.WriteLine("Grade Calculator: ");
Console.WriteLine();
}
static double Calculate()
{
Console.WriteLine("Enter grades (-99 to exit): ");
string input = Console.ReadLine();
int[] array1 = new int[] { };
int iInput = int.Parse(input);
int min = 100;
int max = 0;
int i = 0;
int sum = 0;
double average = 0;
while(iInput != 99)
{
if(iInput < min)
{
array1[i] = min;
}
else if(iInput > max)
{
array1[i] = max;
}
sum += iInput - (min + max);
i++;
}
average = (double)sum / i;
return average;
}
}
What do you think could be improved in order for the program to work?

As I mentioned in the comments, you create an array of size zero. I don't see why you need an array at all, since you are only summing the values:
static double Calculate()
{
Console.WriteLine("Enter grades (-99 to exit): ");
int min = Int32.MaxValue;
int max = Int32.MinValue;
int sum = 0;
int i = 0;
while (true)
{
// TODO: Change to TryParse and handle input errors.
int iInput = int.Parse(Console.ReadLine());
if (iInput == -99) break;
if (iInput > 0 && iInput < 100) {
if (iInput < min)
{
min = iInput;
}
if (iInput > max)
{
max = iInput;
}
sum += iInput;
i += 1;
}
}
// TODO: Ensure no division by zero
return (double)(sum - max - min) / (i - 2);
}

C#: Generate 100 random numbers between 1-1000 and output the max value

I'm very new to coding and I just can't wrap my head around Loops/Arrays/Randoms. I understand the concept but when it comes to applying it, I'm just lost.
Here I'm trying to generate 100 random numbers between 1-1000 and it has to output the maximum value. Here's my code so far:
Random rnd = new Random();
int nums = rnd.Next(0, 1001);
for (int i = 1; i <= 100; i++)
{
}
Console.WriteLine(nums);
Console.ReadLine();
It's only giving me one number. :(
I'd greatly appreciate any help!
Thanks!

You can accumulate your random generated number to the array and then by using Max function of the array you can find the maximum value
class Program
{
public static void Main(string[] args)
{
Random rnd = new Random();
int[] intArr = new int[100];
for (int i = 0; i < intArr.Length; i++)
{
int num = rnd.Next(1, 1000);
intArr[i] = num;
Console.WriteLine(num);
}
Console.WriteLine();
int maxNum = intArr.Max();
Console.WriteLine("The max num is:" + maxNum);
Console.ReadLine();
}
}
Click to watch online demo

You need to call rnd.Next() inside loop.
Random rnd = new Random();
for (int i = 1; i <= 100; i++)
{
int nums = rnd.Next(0, 1001);
Console.WriteLine(nums);
}
Console.ReadLine();

A good approach would be initializing a variable that stores your max. Then generate a random number within your iterative block and if it is greater than your max, set it as the new max.
Random r = new Random();
int max = 0; //declare our max variable
for(int i = 0; i < 100; i++)
{
int rand = r.Next(0, 1001);
if(rand > max) //if the new random value is greater than our max, set max = rand
max = rand;
}
Console.WriteLine(max); //Output the maximum value
Console.ReadLine();
If you want to output every random value and then output the max out of all the values generated, simply modify the code above by outputting rand within your loop as well.
Hope this helps!

I am not sure, are you asking like this?
Random random = new Random();
int[] nums = new int[100];
// when for loop ends, nums are full of 100 numbers
for (int i = 0; i < nums.Length; i++)
{
int newNum = random.Next(1, 1000);
// show every number
Console.WriteLine(newNum);
nums[i] = newNum;
}
// get the max number
var maxNum = nums.Max();
Console.WriteLine(maxNum);

If you want to see the code for Loops/Arrays/Randoms all working together you can use the below with the comments walking through what each line is doing (Working .NET Fiddle Example)
public static void Main()
{
// Pass in what range we want our randomly generated numbers to be in
// In your case, between 1 - 1000 and we want to create 100 of them.
//(See GenerateRandomNumbers())
var random = GenerateRandomNumbers(1, 1000, 100);
//Take our newly returned randomly created numbers and
//pass them to our GetMaxNumber method so it can find the Max number
//See (GetMaxNumber())
var result = GetMaxNumber(random);
//We now have our max number; print it to the Console.
Console.WriteLine("Max: " + result);
}
public static int GetMaxNumber(params int[] inputs)
{
//Create a variable that will store the largest number we find in our array
int max = inputs[0];
//Iterate (loop) through all of the 100 values in our array that we passed in
//Here we define "input" which will hold the value for each value in inputs as we check
//if the value of input is greater than our current value of max. If it is greater than our
//current value of max, then we need to update max to now be equal to the value of our input.
//Note: it will do this comparison 100 times beginning with the first value in the inputs array
foreach (var input in inputs)
{
if (input > max)
{
//input's value is greater than the current value of max; update max so that it is equal to the current value of input.
max = input;
}
//no more code; return to top of foreach loop and set input to the next value in inputs
}
//When we get here, it means our foreach loop has completed going through and comparing all 100 values of inputs to see which value is the largest.
//now return this value to Main()
return max;
}
public static int[] GenerateRandomNumbers(int beginRange, int endRange, int maxNumbers)
{
// Instantiate random number generator
Random rnd = new Random();
//Generate and display
int[] intArr = new int[maxNumbers];
//Generate 100 numbers with numbers between 1 and 1000
for (int i = 0; i < intArr.Length; i++)
{
int num = rnd.Next(beginRange, endRange);
intArr[i] = num;
}
return intArr;
}

Display sum of 10 input numbers but take out highest and lowest number

I want to input 10 numbers and get the total sum of them if you take out the highest and lowest number that was input. So basically it'll be 8 numbers that i get the sum of when i take out the highest and lowest number that was input out of the 10. So far i can only count the total sum out of the 10 numbers, but not sure how to take out the highest and lowest. What approach could i take?
static void Main(string[] args)
{
int number, sum = 0, n;
for (number = 1; number < 11; number++)
{
Console.WriteLine("Enter a number");
n = Convert.ToInt32(Console.ReadLine());
sum += n;
}
Points(sum);
Console.ReadLine();
}
static void Points(int sum)
{
Console.WriteLine("Totalpoint is " + sum);
}

Addition is additive, so you can simply remove them on the end:
int sum = 0;
int min = int.MaxValue;
int max = int.MinValue;
for (int i = 0; i < 10; ++i)
{
Console.WriteLine("Enter a number");
int n = Convert.ToInt32(Console.ReadLine());
sum += n;
min = Math.Min(min, n);
max = Math.Max(max, n);
}
sum -= min;
sum -= max;
Points(sum);
Console.ReadLine();

An easy implementation to explain my thought process, could be the following:
static void Main(string[] args)
{
int number, sum = 0, n;
List<int> inputNumbers = new List<int>();
for(number = 0; number < 10; number++)
{
inputNumbers.Add(Convert.ToInt32(Console.ReadLine()));
}
// Obtain maximum and minimum values
var maximum = inputNumbers.Max();
var mimimum = inputNumbers.Min();
foreach (var item in inputNumbers)
{
if(item == maximum)
{
inputNumbers.Remove(item);
break;
}
}
foreach(var item in inputNumbers)
{
if(item == mimimum)
{
inputNumbers.Remove(item);
break;
}
}
Console.WriteLine("Sum: "+inputNumbers.Sum());
Console.ReadKey();
}
The solution is rather simple, since after populating the List with the specified 10 values, you query it to obtain the minimum and maximum values.
When you know them, you can simply loop through the list and remove both the maximum and minimum (break is completely necessary after those operations).
Downside? In this simple implementation, you would be iterating through the List two times, which should definitely be optimized, even if for clean code sake.
But it might the best first step to you!

Just have two more variables to track max and min values as you read them:
min = Math.Min(min, n);
max = Math.Max(max, n);
Then, as you exit the loop, you can simply subtract those from the total sum before printing.
sum -= min + max;

You can try this:
List<int> testNum = new List<int>();
int num = 0;
int sum = 0;
try
{
// This will loop until you have 10 inputs
while(testNum.Count < 10)
{
Console.WriteLine("Enter a number:");
num = Convert.ToInt32(Console.ReadLine()); // Need to have the Try/Catch in case user doesn't input a number
testNum.Add(num);
}
// Get the min and max values (you will need System.Linq for this)
int minVal = testNum.Min();
int maxVal = testNum.Max();
// Remove the min and max values from the List
testNum.Remove(testNum.IndexOf(minVal));
testNum.Remove(testNum.IndexOf(maxVal));
// Sum the remaining values up
foreach(int n in testNum)
{
sum = sum + n;
}
return sum;
}
catch
{
throw;
}

Add the input numbers in the List and sum their values excluding min and max values
public static void Main(string[] args)
{
var list = new List<int>();
for (int i = 0; i < 10; i++)
{
Console.WriteLine("Enter number " + i);
int num = Convert.ToInt32(Console.ReadLine());
list.Add(num); //adding the input number in list
}
Sum(list);
}
private static void Sum(List<int> list)
{
int max = list.Max();
int min = list.Min();
int sum = list.Where(x => x != max && x != min).Sum(); //taking the sum of all values exlcuding min and max
Console.WriteLine("Sum is " + sum);
}

C# Arrays in a Bowling Program. Wont use Lowest Score

I am trying to create a bowling program that when you enter in your name followed by your score, it will take the average, lowest, and highest scores of the players and print them. However for some reason I cannot get the lowest score to print, as when I hit enter twice, it will use the blank value instead of the lowest entered value and name. How can I fix this so that it will display the lowest score?
{
class Program
{
static void Main(string[] args)
{
const int SIZE = 10;
int i;
// create an array with 10 elements
string[] scoreInfo = new string[SIZE];
string[] names = new string[SIZE];
int[] scores = new int[SIZE];
for (i = 0; i < SIZE; i++)
{
// Prompt the user
Console.Write("Enter your first name and score on one line");
Console.WriteLine(" separated by a space.");
// Read one line of data from the file and save it in inputStr
string inputStr = Console.ReadLine( );
// if statement to break when the user enters a zero
if (inputStr == String.Empty)
{
break;
}
// The Split method creates an array of two strings
scoreInfo = inputStr.Split();
// Parse each element of the array into the correct data type
names[i] = scoreInfo[0];
scores[i] = int.Parse(scoreInfo[1]);
}
Console.WriteLine("The avarage score is {0}", AverageScore(scores, i));
Console.WriteLine("{0} scored the lowest at {1}", names[LowScore(scores, i--)], scores[LowScore(scores, i--)]);
Console.WriteLine("{0} scored the highest at {1}", names[HighScore(scores)], scores[HighScore(scores)]);
Console.ReadLine();
Console.ReadLine();
}
static int LowScore(int[] scores, int j)
{
int min = scores.Min();
return Array.IndexOf(scores, min);
}
static int HighScore(int[] scores)
{
int max = scores.Max();
return Array.IndexOf(scores, max);
}
static double AverageScore(int[] numbers, int j)
{
double average = 0;
for (int i = 0; i < j--; i++)
{
int product = 1;
product = numbers[i] * product;
average = product / j;
}
return average;
}
}
}

Use a different data structure and make less work for yourself.
Start with a dictionary that maps names to scores so that you don't have to mess around with indexes.
Then, LINQ is your friend, as you've already noticed. You don't need to create functions for things that already exist (like min/max/average).
eg.
Dictionary<string, int> ranking = new Dictionary<string, int>();
ranking.Add("adam", 20);
ranking.Add("bill", 10);
ranking.Add("carl", 30);
double avg = ranking.Average(kvp => (double)kvp.Value);
var sorted = ranking.OrderBy(kvp => kvp.Value);
var min = sorted.First();
var max = sorted.Last();
Console.WriteLine("Average: {0}", avg);
Console.WriteLine("Lowest: {0} with {1}", min.Key, min.Value);
Console.WriteLine("Highest: {0} with {1}", max.Key, max.Value);

Modify your Average function like this:-
static double AverageScore(int[] numbers, int j)
{
double sum = 0;
for (int i = 0; i < j; i++)
{
sum += numbers[i];
}
return (double)sum / j;
}
I am not sure why you were taking product of items for finding average of scores.
And Your Min function like this:-
static int LowScore(int[] scores, int j)
{
int min = scores.Where((v, i) => i < j).Min();
return Array.IndexOf(scores, min);
}
Here, you are passing the complete array of integer, so if only 3 players entered values, rest of the values will be initialized to default, i.e. 0 for int, Thus you were getting 0 as Min value.
Also, You need to change the method invocation like this:-
Console.WriteLine("{0} scored the lowest at {1}", names[LowScore(scores, i)], scores[LowScore(scores, i)]);

Index out of Range exception in C# when iterating through an array

I have this code I'm using to create a program that takes a a range and outputs to the Console the prime numbers. I have one problem, I'm trying to iterate through the array I built so the loop should only write to the console the values that are prime using my method's return value. The problem I'm having is that I have the second condition set to numArray.Length but it seems to give me the Index out of Range Exception. I just want the loop to iterate through all values in the numArray and stop when it's done figuring out whether the last value is prime or not.
public struct Prime
{
public int x;
// constructor for Prime
public Prime(int x1)
{
x = x1;
}
public int IsPrime(int number)
{
int i;
for (i = 2; i * i <= number; i++)
{
if (number % i == 0) return 0;
}
return 1;
}
}
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter an Integer");
int num1 = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Enter a Second Integer of Greater Value");
// int num2 = 0;
int num2 = Convert.ToInt32(Console.ReadLine());
/* if (num2temp > num1)
{
num2temp = num2;
}
else
{
Console.WriteLine("You Did Not Enter An Integer Greater Than the First Integer, Please Enter Your Integers Again.");
Environment.Exit(0);
}
*/ int index = 1;
int[] numArray = new int[num2];
for (int i = num1; i <= num2; i++)
{
numArray[index] = i;
Console.WriteLine(" index: {0} assignment: {1}", index, i);
index++;
Console.WriteLine("index: {0}",index);
}
Console.WriteLine("value: {0}", numArray[40]);
/* Prime myprime = new Prime();
if (myprime.IsPrime(numArray[12]) == 1)
{
Console.WriteLine("true");
}
else
{
Console.WriteLine("False");
} */
Prime myprime = new Prime();
int value = 0;
for (int y = 1; y <= num2; y++)
{
if (myprime.IsPrime(numArray[y]) == 1)
{
value = numArray[y];
Console.Write("{0} \t", value);
}
}

You're currently trying to iterate up to and including the size of the array. Arrays are 0-indexed in C#. So this:
int[] numArray = new int[num2];
for (int i = num1; i <= num2; i++)
should be:
for (int i = num1; i < num2; i++)
And note that to get at the first element array, num1 would have to be 0, not 1.
Likewise, your initial assignment of index as 1 should be 0 instead. Basically you need to go through all your code (it's confusing at the moment with lots of bits commented out) and check everywhere that you're assuming arrays are 1-based, and instead change your code as they're 0-based.
(In some cases you may just want to make the array one bigger, of course. If you want an array which logically contains the values 1 to x inclusive, you can either create an array of size x and subtract one from each index all the time, or create an array of size x + 1.)

Your index starts from 1 but should start from 0:
int index = 0; //CHANGE HERE
int[] numArray = new int[num2];
for (int i = num1; i <= num2; i++)
{
numArray[index] = i;
Console.WriteLine(" index: {0} assignment: {1}", index, i);
index++;
Console.WriteLine("index: {0}",index);
}
and then here y should also be 0 and check should if it is less than num2:
for (int y = 0; y < num2; y++)
{
if (myprime.IsPrime(numArray[y]) == 1)
{
value = numArray[y];
Console.Write("{0} \t", value);
}
}
because array indexing in C# start from 0.