C#•2y ago

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

31 Replies

Kouhai•2y ago

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

hanu•2y ago

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

hercules_x_x•2y ago

so how to remove the error

Kouhai•2y ago

Do you know how for loops work?

Hulkstance•2y ago

foreach (var i in Enumerable.Range(0, days.Length) or for (var i = 0; i < days.Length; i++) hf

Kouhai•2y ago

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

Hulkstance•2y ago

true 😄

hercules_x_x•2y ago

i swear i found why before i read lol just now after i keep thinking of this i did this yes u ever explain to me there is another thing actually i wana ask if that is ok

Kouhai•2y ago

Yeah sure go ahread

hercules_x_x•2y ago

there is weird yellow warning teacher she keep saying ignore it It’s appear in readline

Kouhai•2y ago

What's the warning?

Hulkstance•2y ago

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

hercules_x_x•2y ago

yessssssss

Hulkstance•2y ago

use Convert.ToDouble(Console.ReadLine()) there is a difference between them if you hover it

hercules_x_x•2y ago

can i understand actually why

Hulkstance•2y ago

double.Parse has an additional ArgumentNullException – s is null. that's why

Kouhai•2y ago

Well, the reason you get this warning is because Console.ReadLine can return null double.Parse doesn't work with null

hercules_x_x•2y ago

i don’t really understand null

Hulkstance•2y ago

Hulkstance•2y ago

hercules_x_x•2y ago

u mean like return value?

Hulkstance•2y ago

Console.ReadLine may be null

Kouhai•2y ago

null means no reference

hercules_x_x•2y ago

ohhhh then what is the real use of parse

Kouhai•2y ago

To parse a string

Hulkstance•2y ago

to try parse to int or something there are two patterns they are referred as Tester-Doer void Parse(...) and bool TryParse(..., out ...)

Hulkstance•2y ago

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

Exceptions and Performance - Framework Design Guidelines

Learn more about: Exceptions and Performance

Kouhai•2y ago

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

Hulkstance•2y ago

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

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

me neither but good to know

hercules_x_x•2y ago

i am a bit lost to be honest

Hulkstance•2y ago

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 let's say you're parsing an .xls document or something and u need to know if a cell is an integer you would do bool isInteger = int.TryParse(cell, out _) did you understand it that way? in your case it's trying to parse the string you write in the console to double

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any thoughts why this error ?