What is readonly variable?

Question

c#

Answer 1

Meaning that you cannot change the variable, its like a constant. You can only access it to read whatever the variable has.

Answer 2

means you cant change it. you can only find out what its value is

Answer 3

...is what i just said

Answer 4

U can use readonly key word only on fields(variables).
U can assign values to readonly variable only on declaration or inside the same class constructor.
for more info: https://msdn.microsoft.com/en-us/library/acdd6hb7.aspx