What will happen to a var type when code block ends?

Question

What is the diference between those two examples of code? public Test(int x) { List list= new List(); List list1 = new List(); list= CreateList(x); list1 = CreateList(x + 1); DoStuff(list, list1); list.Clear(); list = null; list1.Clear(); list1 = null; } Is this the way to code? public Test(int nCount) { var list = CreateList(nCount); var list1 = CreateList(nCount + 1); DoStuff(list, list1); } JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

You're not actually comparing like with like as all var means is "let the compiler decide what type this is". It will compile to the same code (assuming that CreateList returns a List). So while your code is functionally identically you're doing extra work in the first example that you're not replicating in the second. In the first case you are creating lists unnecessarily as the act of returning a list from CreateList(x) will overwrite what you have just created. A more accurate question would be asking for this difference between: public Test(int x) { List list= CreateList(x); List list1 = CreateList(x + 1); DoStuff(list, list1); list.Clear(); list = null; list1.Clear(); list1 = null; } and public Test(int nCount) { var list = CreateList(nCount); var list1 = CreateList(nCount + 1); DoStuff(list, list1); } In both cases as the lists fall out of scope they'll be marked as eligible for garbage collection. You don't need the calls to Clear() or to set the variables to null.