CODEWITHSUNDEEP
c#
Mohamed Mostafa
Mohamed Mostafa

Reputation: 25

Converting a string getting Wrong value

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

Upvotes: 2

Views: 237

Answers (4)

Gerardo Grignoli
Gerardo Grignoli

Reputation: 15167

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';

Upvotes: 0

Peru
Peru

Reputation: 2971

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

Upvotes: 0

Blue
Blue

Reputation: 22911

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()));

Upvotes: 2

tim
tim

Reputation: 114

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

Upvotes: -1

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