Can someone help me finish this challenge?

Question

I try to change some values of the Dictionary while iterating, but it give me an exception
https://code.sololearn.com/cpAD7MyC1Hs6/?ref=app

Answer 1

That exception is kinda tricky the only thing you need to do is to use ToList() function

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Sololearn
{
class Program
{
static void Main(string[] args)
{

int discount = Convert.ToInt32(Console.ReadLine());
Dictionary<string, int> coffee = new Dictionary<string, int>(); coffee.Add("Americano", 50);
coffee.Add("Latte", 70);
coffee.Add("Flat White", 60);
coffee.Add("Espresso", 60);
coffee.Add("Cappuccino", 80);
coffee.Add("Mocha", 90);
foreach(string x in coffee.Keys.ToList())
{ coffee[x]-=coffee[x]*(discount/100); }
}
}
}

Answer 2

You accidently wrote "can" at line 7 gotta delete that line.

Idk the requirement of the task, but I was wondering why you choose to modify the dictionary values when you can just print them out with some adjustments taking <discount> value into consideration.

double discountPercent = 1.0 - discount / 100.0;
//Console.WriteLine( discountPercent );
foreach( string key in coffee.Keys.ToArray() )
{
coffee[ key ] = ( int ) ( ( double )coffee[ key ] * discountPercent );
Console.WriteLine( coffee[ key ] );
}

Answer 3

int discount = Convert.ToInt32(Console.ReadLine());
Dictionary<string, int> coffee = new Dictionary<string, int>();
coffee.Add("Americano", 50);
coffee.Add("Latte", 70);
coffee.Add("Flat White", 60);
coffee.Add("Espresso", 60);
coffee.Add("Cappuccino", 80);
coffee.Add("Mocha", 90);

foreach (KeyValuePair<string, int> entry in coffee)
{
Console.WriteLine(entry.Key + ": " + (entry.Value - entry.Value * discount / 100));
}