Twenty C# Questions Explained

Naman Kumar XI V.V.D.A.V Public School New Delhi

Jump Start Target Agenda#1: When to Use a struct vs Class

#6: How would you count the occurrences of a string within a string?

#11: Encrypt/Decrypt a String in .NET

#16: How do I Make a Texbox that Only Accepts Numbers?

#2: How Does One Parse XML Files?

#7: How to Check if a Number is a Power of 2

#12: How do I Get the Index of the Current Iteration of a foreach Loop?

#17: How do I Round a Decimal Value to 2 Places for Output?

#3: What is the Difference between String and string

#8: C# Loop – break vs continue

#13: How to Get My Own IP address in C#

#18: Remove Duplicates from an Array

#4: How do I get the Application’s Path in a C# Console App?

#9: Difference Between abstract and virtual functions

#14: How do I Calculate Someone’s Age in C#?

#19: How do I Sort a Dictionary by Value?

#5: Calling base Constructor in C#

#10: Difference Between ref and out Keywords

#15: How do I get the String Value of an enum?

#20: How Can I Return Multiple Values From a Function in C#?

#1: When to Use a struct vs Class

• structs are value types that can contain data and functions• structs are value types and do not require heap allocation. • structs directly store their data in the struct, classes store a reference to a dynamically allocated object. • structs are useful for small data structures • structs can affect performance• Constructors are invoked with the new operator, but that does not allocate memory on the heap• A struct constructor simply returns the struct value itself (typically in a temporary location on the stack),

and this value is then copied as necessary

#1: When to Use a struct vs Class, Cont’d• With classes, multiple variables may have a reference to the same object• It is possible for operations on one variable to affect the object referenced by the other variable.• With structs, the variables each have their own copy of the data, and it is not possible for operations on

one to affect the other. • structs do not support user-specified inheritance, and they implicitly inherit from type object