c# - "stringDemo" versus new string("stringDemo".ToCharArray); -


please @ below code: 

using system; class myclass {     static void main()     {         object o = ".net framework";         object o1 = new string(".net framework".tochararray());         console.writeline(o == o1);         console.writeline(o.equals(o1));     } }

and result is:
false
true

and consider one:

using system; class myclass {     static void main()     {         object o = ".net framework";         object o1 = ".net framework";         console.writeline(o == o1);         console.writeline(o.equals(o1));     } }

and result is:
true
true

“==” compares if object references same while “.equals()” compares if contents same. , want know different between these codes?!

object o1 = new string(".net framework".tochararray());

and 

object o1 = ".net framework";

both of them turn out object why results different?

both of them turn out object why results different?

in second case, you're using same string constant both o , o1 assignment. c# guarantees 2 equal string constant expressions within same program refer same string object. values of o , o1 same reference.

while can't find more general form (for constant string expressions), case covered section 2.4.4 of c# spec:

when 2 or more string literals equivalent according string equality operator appear in same program, these string literals refere same string instance.

edit: quick note on behaviour of ==:

  • if both operands have compile-time type of ==, overload provided string used, performs content comparison
  • otherwise, "default" implementation compares references equality used, stated in question.

in case, compile-time types of operands both object, genuinely using reference equality.


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