Why do commas not work to include strings in WriteLine?

I am wondering why a '+' is needed in a scenario like this:

string name = "Rick";
Console.WriteLine("Hello, " + name);


I was under the impression that the '+' was needed to include a variable of another type, and a string could be included without one. Is this incorrect?

Further, if that is the case, then why does it simply skip the variable and not return an error in a situation like this:

string name = "Rick";
Console.WriteLine("Hello, " , name);


Thanks.

4 Answers
4

As far as the compiler is concerned, the second version is trying to pass a second parameter, which the WriteLine method is not overloaded for. The options you really have for this are as follows

WriteLine

Console.WriteLine("Hello, " + name);
Console.WriteLine($"Hello, name");
Console.WriteLine(String.Format("Hello, 0", name));


WriteLine()

Format()

C# concatenates string using operator +. So, one strings adds to another string creating third string containing first and second strings. Comma does not concatenate strings, comma separates parameters.

+

You're getting confused. in your first example:

Console.WriteLine("Hello, " + name);


the two strings are being concatenated, and the result is being passed as a parameter to the Console.WriteLine method.

Console.WriteLine

The second example:

Console.WriteLine("Hello, " , name);


is actually calling a different overload of that method, that accepts a string and an object.

The first Example:

string name = "Rick"; //string variable
Console.WriteLine("Hello, " + name);


the + operator is used to concatenate the value of string variable name and the string literal "Hello, ".

+

name

"Hello, "

The resulting output will be Hello, Rick

Hello, Rick

For more see:String Concatenation

The second example:

string name = "Rick";
Console.WriteLine("Hello, " , name);


Matches the overload
Console.WriteLine(String, Object)

It requires the use of a formatter 0 because the formatter is not present nothing will happen with the second argument Object (in your case in the variable name). A proper version of this would be written as :

0

Object

name

string name = "Rick";
Console.WriteLine("Hello, 0", name);

string name = "Rick";
Console.WriteLine("Hello, 0", name);

The object is cast to string and creates a new string with the value of name replacing the 0 value.


The resulting output that is written to screen would be:Hello, Rick

0

Hello, Rick

For more info I'd recommend you look at the following:

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