CODEWITHSUNDEEP
c#
yuriko
yuriko

Reputation: 33

int to char array

static void Main(string[] args)
{
    int num = 382;
    int output = 0;
    char[] nlst = num.ToString().ToCharArray();
    for (int i = 0; i < nlst.Length; i++)
    {
        output += nlst[i];
    }
    Console.WriteLine(output);
    Console.ReadLine();
}

The output result is 157, Actually it should be 13.With Dedbugging I found the 3 elements of char[] nlst like this :

[0]51'3', [1]56'8', [2]50'2'

Why? What's the meaning of 51,56,50?

Upvotes: 3

Views: 28370

Answers (7)

user319785
user319785

Reputation: 31

The correct solution is

output += Convert.ToInt32(nlst[i]) - '0';

or briefly

output += nlst[i] - '0';

or, as an alternative

output += Convert.ToInt32(Convert.ToString(nlst[i]));

Please note: As well as C++, C# Convert.ToInt32 converts chars to basic Unicode (i.e. good old Ascii).

Upvotes: 0

Matthew Watson
Matthew Watson

Reputation: 109557

You're assuming that the char value of '0' is 0. It is not; it is in fact the UTF16 value of '0' which is 48.

So you are adding together the UTF16 values of the characters '3', '8' and '2', i.e. 51, 56 and 50.

Note that if your aim is to add together all the digits of an integer, the best approach is to avoid converting to a string completely, like so:

int num = 382;

// Compute the sum of digits of num

int total = 0;

while (num > 0)
{
    total += num%10;
    num /= 10;
}

Console.WriteLine(total);

However if you just want to know how to get your version working, just subtract '0' from each character before adding the codes together. That will convert '0' to 0, '1' to 1, etc:

for (int i = 0; i < nlst.Length; i++)
{
    output += nlst[i] - '0'; // Subtract '0' here.
}

Upvotes: 13

Michal
Michal

Reputation: 61

[EDITED] Char is unicode 16 (https://msdn.microsoft.com/en-us/library/x9h8tsay.aspx). You can use int.Parse

static void Main(string[] args)
{
    int num = 382;
    int output = 0;
    char[] nlst = num.ToString().ToCharArray();
    for (int i = 0; i < nlst.Length; i++)
    {
        output += int.Parse(nlst[i].ToString());

    }
    Console.WriteLine(output);
    Console.ReadLine();
}

Upvotes: 0

haim770
haim770

Reputation: 49095

You need to convert the char back to its numeric value.

Try this:

output += Convert.ToInt32(Char.GetNumericValue(nlst[i]));

Upvotes: 0

KampfFussel
KampfFussel

Reputation: 137

Your output variable is defined as an integer. If you add (+=) a char to an integer, it's unicode value will be added to the output variable.

    static void Main(string[] args)
{
    int num = 382;
    int output = 0;
    char[] nlst = num.ToString().ToCharArray();
    for (int i = 0; i < nlst.Length; i++)
    {
        output += Convert.ToInt32(nlst[i]);

    }
    Console.WriteLine(output);
    Console.ReadLine();
}

Upvotes: 0

TheCodingDamian
TheCodingDamian

Reputation: 443

Those numbers are the char codes of the numbers. If you just want to add up the value of each Digit, you can subtract 48 from each char value to turn it into ist number value 

for (int i = 0; i < nlst.Length; i++)
{
    output += nlst[i] - 48;
}

Upvotes: 0

EvilTak
EvilTak

Reputation: 7579

Those are the Unicode values for '3', '8' and '2' respectively.

To convert an Unicode value (eg. 51) to the integer representation of the character represented by the Unicode value (eg. 3), use the Convert.ToInt32(char) method.

Upvotes: 2

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