any thoughts why this error ? Unhandled exception. System.IndexOutOfRangeException: Index was outside the bounds of the array. at inclass7.exercise7_1.Main(String[] args) in /Users/user/EXSAM/Program.cs:line 17

help

Root Question Message

Hercules_x_x10/28/2022

any thoughts why this error ?

Unhandled exception. System.IndexOutOfRangeException: Index was outside the bounds of the array.
at inclass7.exercise7_1.Main(String[] args) in /Users/user/EXSAM/Program.cs:line 17

Kouhai10/28/2022

i <= days.Length
Means run till i equals the length of days array
arrays in c# start at 0

한우10/28/2022

if you count from 0 to n, that's total (n+1) numbers

Hercules_x_x10/28/2022

so how to remove the error

Kouhai10/28/2022

Do you know how for loops work?

Electron10/28/2022

foreach (var i in Enumerable.Range(0, days.Length)

Electron10/28/2022

or for (var i = 0; i < days.Length; i++)

Electron10/28/2022

Kouhai10/28/2022

😅 They'll just copy paste it and won't understand why that's the solution

Electron10/28/2022

true 😄

Hercules_x_x10/28/2022

i swear i found why before i read lol

Hercules_x_x10/28/2022

just now after i keep thinking of this

Hercules_x_x10/28/2022

i did this

Hercules_x_x10/28/2022

yes u ever explain to me

Hercules_x_x10/28/2022

there is another thing actually i wana ask if that is ok

Kouhai10/28/2022

Yeah sure go ahread

Hercules_x_x10/28/2022

there is weird yellow warning

Hercules_x_x10/28/2022

teacher she keep saying ignore it

Hercules_x_x10/28/2022

It’s appear in readline

Kouhai10/28/2022

What's the warning?

Electron10/28/2022

you do double.Parse(Console.ReadLine())?

Hercules_x_x10/28/2022

yessssssss

Electron10/28/2022

use Convert.ToDouble(Console.ReadLine())

Electron10/28/2022

there is a difference between them if you hover it

Hercules_x_x10/28/2022

can i understand actually why

Electron10/28/2022

double.Parse has an additional ArgumentNullException – s is null.

Electron10/28/2022

that's why

Kouhai10/28/2022

Well, the reason you get this warning is because Console.ReadLine can return null

Kouhai10/28/2022

double.Parse doesn't work with null

Hercules_x_x10/28/2022

i don’t really understand null

Electron10/28/2022

Hercules_x_x10/28/2022

u mean like return value?

Electron10/28/2022

Console.ReadLine may be null

Kouhai10/28/2022

null means no reference

Hercules_x_x10/28/2022

ohhhh

Hercules_x_x10/28/2022

then what is the real use of parse

Kouhai10/28/2022

To parse a string

Electron10/28/2022

to try parse to int or something

Electron10/28/2022

there are two patterns

Electron10/28/2022

they are referred as Tester-Doer

Electron10/28/2022

void Parse(...) and bool TryParse(..., out ...)

Electron10/28/2022

https://learn.microsoft.com/en-us/dotnet/standard/design-guidelines/exceptions-and-performance#tester-doer-pattern

Kouhai10/28/2022

I don't think they were taught the out key word 😅

Electron10/28/2022

public struct DateTime
{
    public static DateTime Parse(string dateTime)
    {
        ...
    }
    public static bool TryParse(string dateTime, out DateTime result)
    {
        ...
    }
}

Electron10/28/2022

me neither

Electron10/28/2022

but good to know

Hercules_x_x10/28/2022

i am a bit lost to be honest

Electron10/28/2022

if something goes sideways in Parse, it's supposed to throw an exception such as InvalidOperationException. TryParse however try/catch'es it, so it never throws and instead it returns a boolean

Electron10/28/2022

let's say you're parsing an .xls document or something

Electron10/28/2022

and u need to know if a cell is an integer

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