char + char = int? Why? [duplicate]

Answer 1

A char or System.Char is an integral type:

An integral type representing unsigned 16-bit integers with values between 0 and 65535. The set of possible values for the type corresponds to the Unicode character set.

This means that it behaves exactly like a uint16 or System.UInt16, and adding chars with the + operator therefore adds the integral values, because the + operator is not overloaded in char.

To concatenate individual chars into a string use StringBuilder.Append(char) or new String(char[]).

Answer 2

char is a value type, meaning it has a numerical value (its UTF-16 Unicode ordinal). However, it is not considered a numeric type (like int, float, etc) and therefore, the + operator is not defined for char.

The char type can, however, be implicitly converted to the numeric int type. Because it's implicit, the compiler is allowed to make the conversion for you, according to a set of rules of precedence laid out in the C# spec. int is one of the first things normally tried. That makes the + operator valid, and so that's the operation performed.

To do what you want, start with an empty string:

var pr = "" + 'R' + 'G' + 'B' + 'Y' + 'P';

Unlike the char type, the string type defines an overloaded + operator for Object, which transforms the second term, whatever it is, into a string using ToString() before concatenating it to the first term. That means no implicit casting is performed; your pr variable is now inferred as a string and is the concatenation of all character values.

Answer 3

It shouldn't because that would be inefficient. If one wanted to concatenate the chars like that they should use string builder. Otherwise each addition would create a temporary memory to hold the concatinated partial string, which would mean that in your example 4 temporary memory allocations would have to occur.

Answer 4

Why is C# designed like this? Wasn't the default implementation of adding two chars should be resulting to a string that concatenates the chars, not int?

What you intended is not correct in respect to what you want to accomplish. A String is not an addition of chars, a String is an addition of so to say "singleton" strings.

So "a"+"b"=>"ab", which is absolutely correct if you take into account, that the + operator for strings is overloaded. And hence 'a' represents the ASCII char 65, it is totally consistent to say, that 'a'+'b' is 131.

Answer 5

A Char is a textual representation of a 16-bit integer value. You are simply adding ints together. If you want to concatenate chars, you'll have to cast them to strings.

Answer 6

From MSDN:

Implicit conversions might occur in many situations, including method invoking and assignment statements.

A char can be implicitly converted to ushort, int, uint, long, ulong, float, double, or decimal. Thus that assignment operation implicitly converts char to int.