int not what I try and assign it

Question

I am learning C# and having an issue understanding why my highNumber value is being displayed as 56 when running my code snippet.

//Write a program and ask the user to enter a series of numbers separated by comma. Find the maximum of the numbers //and display it on the console. For example, if the user enters “5, 3, 8, 1, 4", the program should display 8

int highNumber = 0;

Console.Write("Enter a series of numbers separated by comma: ");
var userInput = Console.ReadLine();

for (var i = 0; i < userInput.Length; i++)
{
    if (char.IsNumber(userInput[i]) == true)
    {
        if (userInput[i] > highNumber)
        {
            highNumber =  Convert.ToInt32(userInput[i]);
        }
    }
}

Console.WriteLine("The largest number is {0}", Convert.ToInt32(highNumber));

Fyi, `Convert.ToInt32(highNumber)` is useless because it's already an `int` — Tim Schmelter, Dec 20 '17 at 15:39
`if (char.IsNumber(userInput[i]) == true)` is also reduntant. use `if ( char.IsNumber(userInput[i]) )` instead — Hemid Abbasov, Dec 20 '17 at 15:41

LordWilmore · Answer 1 · 2017-12-20T15:41:41.373

3

You've entered the ASCII character '8', which has the numeric value 56.

If it's a single digit character then convert it with this

int val = (int)Char.GetNumericValue(userInput[i]);

If it's a numeric string then convert it in one call with this

int val;
bool success = Int32.TryParse(userInput, out val);

or

int val = System.Convert.ToInt32(userInput);

edited Dec 20 '17 at 15:41

answered Dec 20 '17 at 15:37

LordWilmore

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I know, sorry, I accidentally closed it when switching tabs. I've updated the answer now – LordWilmore Dec 20 '17 at 15:38
Note that this only works for single digit values. It breaks if the input is `"128,12,5"`. – René Vogt Dec 20 '17 at 15:40
Worth adding the documentation: https://msdn.microsoft.com/en-us/library/ww9t2871(v=vs.110).aspx – Tim Schmelter Dec 20 '17 at 15:40
I recommend against using `Int32` and in favour of `int`, as highlighted [here](https://stackoverflow.com/a/62738/501011) – MechMK1 Dec 20 '17 at 15:41

Rey · Accepted Answer · 2017-12-20T16:08:04.833

The LordWilmore`s answer is somehow correct if you dont use numbers greater than 10 but you can simplify and make it more accurate as below:

int highNumber = 0;
int valueTemp;
Console.Write("Enter a series of numbers separated by comma: ");
var userInput = Console.ReadLine();
string[] array = userInput.Split(',');

for (var i = 0; i < array.Length; i++)
{
    if (int.TryParse(array[i], out valueTemp))
    {
        if (valueTemp > highNumber)
        {
            highNumber =  valueTemp;
        }
    }
}

Console.WriteLine("The largest number is {0}", highNumber);

or using Max() function if you have knowledge about the List<> in c#:

int valueTemp;
Console.Write("Enter a series of numbers separated by comma: ");
var userInput = Console.ReadLine();
string[] array = userInput.Split(',');
List<int> intList = new List<int>();

for (var i = 0; i < array.Length; i++)
{
    if (int.TryParse(array[i], out valueTemp))
    {
        intList.Add(valueTemp);
    }
}
Console.WriteLine("The largest number is {0}", intList.Max());

This is a more accurate example because if put 3,33,4 in your example it will fail since you get each character and not values separated by comma. In my case I split them into pieces accordingly and then continue to test them appropriately.

Thank you, this worked great. Looks like turning it into an array was what I was missing. — TJ2, Dec 20 '17 at 16:07

score 1 · Answer 3 · answered Dec 20 '17 at 15:55

Console.ReadLine(); returns a string. When you use the indexer ([i]) on the string you get individual characters, not strings or numbers. What you want is to Split the string by the commas, then use TryParse to ensure that each string is a number:

string userInput = Console.ReadLine();
string[] parts = userInput.Split(',');
for (var i = 0; i < parts.Length; i++)
{
    int number;
    if (int.TryParse(parts[i], out number))
    {
        if (number > highNumber)
        {
            highNumber = number;
        }
    }
}

int not what I try and assign it

3 Answers3