Assigining string to string array

You can't "assign a string value in a string array" - you can assign a strign vlaue to an element of a string array, but you can only assign arrays to arrays and vice versa.
So you can do this:

string s = "Hello there";
string[] arr = new string[5];
arr[2] = s;

But you can't do this:

string s = "Hello there";
string[] arr = s;

because the types are not compatible.

You can use Split to break a string into an array of substrings:

string s = "Hello there";
string[] arr = s.Split(' ');

which will give you an array of two strings, containing "hello" and "there".
This is very useful when separating user input strings for example:

string s = "Smith;John;2 Letsbe Avenue, Luton";
string[] arr = s.Split(';');

would break the input into the various address parts.