C# Language

1. C# Language MIS 324 Professor Sandvig

2. Overview • Why learn C#? • C# Basics • Variables • Data types • Operators • Control Structures

3. Why Learn C#? • Modern language • Microsoft introduced in 2000 • More user-friendly than older languages • Managed code • Memory allocation • Garbage collection • 100% object oriented • Widely used

4. Variables • C# strongly typed • Similar to VB.NET • PHP loosely typed • Strongly typed: • A variable accepts only one data type • Type is explicitly declared when variable is declared

5. Variables • Strongly Typed • Advantage • Less error prone • Compiler more likely to catch programming errors • Disadvantage • More explicit data type conversions

6. Variables • Variables are objects • Have properties & methods FName = FName.Replace(“S”,”P”);

7. Variables • Commonly Used C# Data Types

8. Datatype Conversion • Implicit Conversion • Done when no data lost

9. Datatype Conversion • Web Forms • Lots of data type conversions • All data from web forms type string • .NET MVC • Data types defined in model • Few datatype conversions needed

10. Variable Scope • Control structures limit variable scope • Where variable is visible • Visible in structure and children

11. Variable Scope • Try to minimize scope • Minimize complexity • “The road to Hell is paved with global variables” Steve McConnell Code Complete 2nd Ed.

12. Variable Scope • Write code to minimize variable scope • Control structures • Classes • Good:

13. Common C# Operators Control Structures examples

14. Control Structures • Syntax similar to C, JavaScript, PHP, Java, … • Curley brackets for statement blocks if (condition) { //Statement block } else { //statement block }

15. Control Structures • May omit brackets for single statements: if (condition) statement 1; else statement 2;

16. Control Structures • Similar in all languages • Syntax may be different • if • for • foreach • while

17. Control Structures • 1. if else: if (condition) { //do something } else if (condition) { //do something } else { //do something else }

18. Control Structures • 2. for statement • increments a counter variable • may declare within statement for (int i = 0; i <= 10; i++) { ViewBag.message += “value of i:” + i + “<br>”; }

19. Control Structures • 3. foreach loop • iterate through collections • arrays, controls, cookies, etc. int[] intArray = {3, 5, 7, 9}; foreach (int item in intArray) { ViewBag.message += “Item: “ + item + “<br>”; }

20. Control Structures • 4. while loop int i = 0; while (i < 5) { i += 1; }

21. Summary • C# modern object oriented programing language • Relatively easy to use • Managed code • C-like syntax (similar toPHP, JavaScript, C, C++) • Strongly typed • Explicitly convert data types • Pick up syntax quickly • Visual Studio big help