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While loop doesnt function when calculatin all positive numbers c#

I am making a while loop. The purpose of the loop is to take all the positive numbers and calculating the average. It works most of the time but not always. Can someone help? here is the code:
double count = 0;
int sum = 0;
int input = -1;
while (input != 0)
{
Console.Write("Enter a number: ");
input = int.Parse(Console.ReadLine());
if (input > 0)
{
sum += input;
count++;
}
if (input < 0)
{
Console.Write("Enter a number: ");
input = int.Parse(Console.ReadLine());
}
}
if (input == 0)
{
Console.Write($"Average of all positive numbers is: { (sum += input) / count:0.00} ");
}

The second if is redundant it should work just like this
while (input != 0) {
Console.Write("Enter a number: ");
input = int.Parse(Console.ReadLine());
if (input > 0)
{
sum += input;
count++;
}
}
Your problem was when you enter a negative number it gives you the option to enter another, but then you enter a new iteration of the while loop and it asks you to enter another number. Removing the second if should fix your problem. Hope i helped :)

This code does not throw exceptions when non numeric data is entered
int count = 0;
long sum = 0;
int input;
Console.Write("Enter a number: ");
while (int.TryParse(Console.ReadLine(), out input))
{
Console.Write("Enter a number: ");
if (input > 0)
{
sum += input;
count++;
}
}
Console.Write($"Average of all positive numbers is: {sum} / {Math.Max(count,1.0)} = {Math.Round( sum / Math.Max(count,1.0), 2)}.");

Making a program that sums up only even numbers entered from console

In one of my classes I was given an assignment to write a simple program that combines multiple numbers entered from the console, but only adding up the even ones. I was able to do the summing up part pretty easily but I can't figure out how to check for even numbers! If anyone can figure out how or explain for a beginner how to do it would be greatly appreciated.
Here's the full code so far:
using System;
namespace Test_3
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Amount of numbers n = ");
var n = int.Parse(Console.ReadLine());
Console.WriteLine("Enter numbers:");
var sum = 0;
for (int i = 0; i < n; i++)
{
if (sum%2 == 0)
{
}
else
{
}
var num = int.Parse(Console.ReadLine());
sum = sum + num;
}
Console.WriteLine("The sum of the numbers is " + sum);
}
}
}

You seem to already know how to get the even numbers but here is how to apply it!
Console.WriteLine("Amount of numbers n = ");
var n = int.Parse(Console.ReadLine());
Console.WriteLine("Enter numbers:");
var sum = 0;
for (int i = 0; i < n; i++)
{
var num = int.Parse(Console.ReadLine()); //first read a number from the console
if (num % 2 == 0) //then check if it is even
{
sum = sum + num; //if it is, then add it to sum
}
}
Console.WriteLine("The sum of the numbers is " + sum);

You seem not to get the idea of an if-clause, let me explain this, using the following pieces of code:
Your code:
for (int i = 0; i < n; i++)
{
if (sum%2 == 0)
{
}
else
{
}
var num = int.Parse(Console.ReadLine());
sum = sum + num;
}
This calculates the sum of all numbers (you check whether a number is even or not, but you don't use that information).
My proposal: (you check if a number is even, and you use that information)
for (int i = 0; i < n; i++)
{
if (sum%2 == 0)
{
var num = int.Parse(Console.ReadLine());
sum = sum + num;
}
else
{
}
}
Another one, how to calculate the sum of the odd numbers? (Here you check if a number is even, but you use the case where it is not)
for (int i = 0; i < n; i++)
{
if (sum%2 == 0)
{
}
else
{
var num = int.Parse(Console.ReadLine());
sum = sum + num;
}
}
So, you see? You can use if-clauses to filter out what you want to do when a condition is met or when a condition is not met, that's the whole idea behind it.

You need to check whether the variable num is divisible by two instead of the sum. The code you have checks if the sum is even and if so does nothing since you didn't add anything to the if statement. Instead, you should be doing if ( num % 2 == 0) .
You also need to move where num is declared to the top of the for loop and move the part where you add to the sum to the inside of the conditional (The if statement).

C# Displaying every other number from a user in a console app

I need to write a console app that asks the user how many number (double) to enter. After accepting that many numbers, display every other number entered. There always seems to be an error when I try to use a double. I also get this error "System.IndexOutOfRangeException was unhandled
HResult=-2146233080
Message=Index was outside the bounds of the array."
after the the for loop has gone through the last loop for this line
myArrai1[i] = int.Parse(Console.ReadLine());
in the first for loop
this all the code I have been able to try to brainstorm with.
class Program
{
static void Main(string[] args)
{
Console.Write("Enter Item Count: ");
int number = int.Parse(Console.ReadLine());
int[] myArrai1 = new int[number];
int i = 0;
for (i = 1; i <= number; i++)
{
Console.WriteLine("Enter Number " + i.ToString() + ": ");
myArrai1[i] = int.Parse(Console.ReadLine());
}
for (i = 0; i < number; i++)
{
Console.WriteLine("Every other number entered: ");
Console.WriteLine(myArrai1[i += 2]);
}
Console.ReadLine();
}
}
}

Not too far off, main changes to fix fix this was loop#1 was set to 0 index to prevent out of range and loop#2 was simplified by intervaling at 2 of ++.
The rest of the changes were aesthetic; I changed the input Console.WriteLine to just Console.Write to keep the input on the same line, and moved the Every Other Line statement to precede the output display loop instead of being written on every iteration.
Console.Write("Enter Item Count: ");
int number = int.Parse(Console.ReadLine());
int[] myArrai1 = new int[number];
for (int i = 0; i < number; i++) {
Console.Write("Enter Number " + (i + 1) + ": ");
myArrai1[i] = int.Parse(Console.ReadLine());
}
Console.WriteLine("Every other number entered: ");
for (int j = 0; j < number; j = j + 2) {
Console.WriteLine(myArrai1[j]);
}

Query regarding calculation of average of some numbers program

I am beginner in C# coding, and I am trying to write some code for the program where my program will show the average of numbers given by users. I have written below code, but I am thinking this would be more better and efficient. Can anyone please help me. Thanks in advance.
static void Main(string[] args)
{
int a=0;
double total = 0;
double result;
Console.Write("For how many numbers you want to do the average calculation: ");
a = int.Parse(Console.ReadLine());
double[] array = new double[a];
for (int j = 0; j < a; j++)
{
Console.Write("Please enter value for {0}: ", j+1);
array[j]= double.Parse(Console.ReadLine());
}
foreach (var item in array)
{
total += item;
}
result = total / a;
Console.WriteLine($"Your Calculated average value is {result}");
Console.ReadKey();
}

You dont need to take extra array for your purpose, you can do this just by adding each input value and then divide that total with total number of input items.
double total = 0;
double result;
Console.Write("For how many numbers you want to do the average calculation: ");
int a = int.Parse(Console.ReadLine());
for (int j = 0; j < a; j++)
{
Console.Write("Please enter value for {0}: ", j + 1);
total += double.Parse(Console.ReadLine());
}
result = total / a;
Console.WriteLine($"Your Calculated average value is {result}");
Console.ReadKey();

while statement-to repeat it again

Everything is allright except the while statement.If you guys can help me that would be great.When the user write "Y" to do it again, he see: max value is: bla bla.
the user has to give a new positive number instead of to see the maximum value over and over again.
Console.WriteLine("Please give a positieve number. if you enter a negatieve number its not going to work");
int invoer = 0, max = 0;
string repeat = "";
do
{
for (int i = 1; invoer >= 0; i++)
{
Console.Write(i + "> ");
invoer = int.Parse(Console.ReadLine());
if (max < invoer)
{
max = invoer;
}
}
Console.WriteLine("Maximum value is: " + max);
Console.WriteLine("do you want to try again? y/n: ");
repeat = Console.ReadLine();
} while (repeat == "y" || repeat == "Y");

Im guessing at what this is supposed to be doing....
{
//Console.WriteLine("Please give a positive number. if you enter a negative number its not going to work");
int invoer;
int max;
string repeat;
do
{
//they have given a negative number and wish to try again
Console.WriteLine("Please give a positive number.\nIf you enter a negative number its not going to work");
invoer = 0;
max = 0;
repeat = "";
for (int i = 1; invoer >= 0; i++)
{
Console.Write(i + "> ");
invoer = int.Parse(Console.ReadLine());
if (max < invoer)
{
max = invoer;
}
}
Console.WriteLine("Maximum value is: " + max);
Console.WriteLine("do you want to try again? y/n: ");
repeat = Console.ReadLine();
} while (repeat == "y" || repeat == "Y");
}

I'm not 100% sure what you're trying to do, but it looks like you need to move your deceleration of invover and max into your do loop.