Converting a string getting Wrong value

Question

I write a simple code and need to get each number in a string as an Integer But when I try to use Convert.ToInt32() it give me another value

Example:

string x="4567";        
Console.WriteLine(x[0]);

the result will be 4 , but if i try to use Convert

Console.WriteLine(Convert.ToInt32(x[0]));

it Give me 52 !!

I try using int.TryParse() and its the same

The ascii value of 4 is 52. http://www.theasciicode.com.ar/ascii-printable-characters/number-four-ascii-code-52.html — Renuka Deshmukh, Jul 27 '16 at 23:11
http://stackoverflow.com/questions/3665757/how-to-convert-char-to-int — Renuka Deshmukh, Jul 27 '16 at 23:13

score 2 · Accepted Answer · answered Jul 27 '16 at 23:12

According to the docs:

The ToInt32(Char) method returns a 32-bit signed integer that represents the UTF-16 encoded code unit of the value argument. If value is not a low surrogate or a high surrogate, this return value also represents the Unicode code point of value.

In order to get 4, you'd have to convert it to a string before converting to int32:

Console.WriteLine(Convert.ToInt32(x[0].ToString()));

score 0 · Answer 2 · answered Jul 27 '16 at 23:13

you can alternatively do this way to loop through all characters in a string

foreach (char c in x)
{
    Console.WriteLine(c);  
}

Will Print 4,5,6,7

And as suggested in earlier answer before converting to integer make that as a sting so it doesn't return the ascii code

score 0 · Answer 3 · answered Jul 27 '16 at 23:59

A char is internally a short integer of it's ASCII representation.

If you cast/convert (explicitly or implicitly) a char to int, you will get it's Ascii value. Example Convert.ToInt32('4') = 52

But when you print it to Console, you are using it's ToString() method implicitly, so you are actually printing the ASCII character '4'. Example: Console.WriteLine(x[0]) is equivalent to Console.WriteLine("4")

Try using an ASCII letter so you will notice the difference clearly:

            Console.WriteLine((char)('a'));  // a
            Console.WriteLine((int)('a'));   // 97

Now play with char math:

            Console.WriteLine((char)('a'+5));  // f
            Console.WriteLine((int)('a'+5));   // 102

Bottom line, just use int digit = int.Parse(x[0]);

Or the funny (but less secure) way: int digit = x[0] - '0';

score -1 · Answer 4 · answered Jul 27 '16 at 23:09

-1

x isnt x[0], x[0] is the first char, '4' which is 52.

answered Jul 27 '16 at 23:09

tim

114
1

what shall i do to get the 4 ? – Mohamed Mostafa Jul 27 '16 at 23:11
Convert.ToInt32(x.Substring(0, 1)); – tim Jul 27 '16 at 23:11

Converting a string getting Wrong value

4 Answers4