C#•9mo ago

In String constructor `String(Char)`, `Char` is character pointer or character array pointer?

I was exploring

System.String

System.String

class here: https://learn.microsoft.com/en-us/dotnet/api/system.string?view=net-9.0

And one of the constructors is

String(Char*)

String(Char*)

Its description says: Initializes a new instance of the String class to the value indicated by a specified pointer to an array of Unicode characters.

However, I got error, when I tried following code to initialize string using pointer to an array of characters:

char[] cArray = {'a','r','r','a','y'};
char[]* cArray_ptr = &cArray;
string s = new string(cArray_ptr); // Error: cannot convert char[]* to char*

char[] cArray = {'a','r','r','a','y'};
char[]* cArray_ptr = &cArray;
string s = new string(cArray_ptr); // Error: cannot convert char[]* to char*

So, my question is:

Is
```
String(Char*)
```
```
String(Char*)
```
takes character pointer as argument instead of character array pointer?
Or am I doing some mistake in declaring and initializing character array pointer?

String Class (System)

Represents text as a sequence of UTF-16 code units.

mg•3/28/25, 5:32 AM

it's a pointer to an array in a C kind of sense

mg•3/28/25, 5:36 AM

the "Pointers and Arrays" section of The C Programming Language would be a good read if you can get a copy of it

mg•3/28/25, 5:37 AM

anything you can do with an array can be done with a pointer, so a is a , in a way. in other ways it's not

reflectronic•3/28/25, 5:37 AM

in terms of the number of indirections, a is the same as , not

reflectronic•3/28/25, 5:38 AM

what you want is to get the of a . you need to use the statement for this

reflectronic•3/28/25, 5:39 AM

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/statements/fixed

fixed statement - pin a moveable variable - C# reference

Use the C# statement to pin a moveable variable and declare a pointer to that variable. The address of a pinned variable doesn't change during execution of the statement.

Angius•3/28/25, 5:48 AM

It's always interesting to me how people take a language that lets you avoid all that pointer tomfuckery, and decide to use pointer tomfuckery anyway :KEKW:

Rreflectronic https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/statements/fi...

yourFriendOP•3/28/25, 6:14 AM

Ok, so in

String(Char*)

String(Char*)

is pointer of first element of character array. If I understand right.

Hence, both way declaring and initializing pointer works

Thanks, the link was very helpful

reflectronic•3/28/25, 6:15 AM

right. well, it's a pointer to whichever element you want to be the first

reflectronic•3/28/25, 6:15 AM

you can give a pointer to and it will create a string starting from there

reflectronic•3/28/25, 6:16 AM

but you have to be careful because this is not a valid usage of

reflectronic•3/28/25, 6:17 AM

the way it calculates the length of the string is by searching for the first character which is in the array your pointer is pointing to, and stopping there

reflectronic•3/28/25, 6:18 AM

you do not have a null character in your array. so your code only works because the memory after the array happens to be empty. it may not always be the case

reflectronic•3/28/25, 6:18 AM

you should include a in your array. or, you can use to provide a start offset and length, so it does not have to search for the

yourFriendOP•3/28/25, 6:19 AM

mg•3/28/25, 5:41 PM

also, like, never do this

mg•3/28/25, 5:42 PM

perfectly fine to play around and explore but is for when you're experienced enough to know how to break the rules the right way in the name of performance

In String constructor `String(Char*)`, `Char*` is character pointer or character array pointer?

In String constructor `String(Char)`, `Char` is character pointer or character array pointer?