1. MIS 324 -- Professor Sandvig MIS 324 Professor Sandvig
11/7/2018
C# Language
MIS 324
Professor Sandvig

2. MIS 324 -- Professor Sandvig
11/7/2018
Overview
Why learn C#?
C# Basics
Variables
Data types
Operators
Control Structures

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

4. MIS 324 -- Professor Sandvig
11/7/2018
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. MIS 324 -- Professor Sandvig
11/7/2018
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. MIS 324 -- Professor Sandvig
11/7/2018
Variables
Commonly Used C# Data Types
int
123
string
“hi”
double
1.23
bool
true
DateTime
Jan. 8, :23:46 pm

8. Datatype Conversion
Implicit Conversion
Done when no data lost

9. Datatype Conversion Web Forms .NET MVC 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 Good:
Control structures
Classes
Good:

13. MIS 324 -- Professor Sandvig
11/7/2018
Common C# Operators
Operator
Function
Example =
Assignment
int a = 3; ==
equality
if (a == 3)
>=
Greater or equal
if (a >= 3) +
Add
int c = 3 + 4;
Concatenate
string s = “Hello ”+ “world”; ++
Increment by 1
i++; +=
Sum
i += 3;
s += “ and other planets”; !
Negate
if(a != b)
Control Structures example

14. MIS 324 -- Professor Sandvig
11/7/2018
Control Structures
Syntax similar to C, JavaScript, PHP, Java, …
Curley brackets for statement blocks
if (condition) {
//Statement block }
else
//statement block

15. MIS 324 -- Professor Sandvig
11/7/2018
Control Structures
May omit brackets for single statements:
if (condition)
statement 1;
else
statement 2;

16. MIS 324 -- Professor Sandvig
11/7/2018
Control Structures
Similar in all languages
Syntax may be different if
for
foreach
while

17. MIS 324 -- Professor Sandvig
11/7/2018
Control Structures
1. if else:
if (condition) {
//do something }
else if (condition)
else
//do something else

18. MIS 324 -- Professor Sandvig
11/7/2018
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. MIS 324 -- Professor Sandvig
11/7/2018
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. MIS 324 -- Professor Sandvig
11/7/2018
Control Structures
4. while loop
int i = 0;
while (i < 5) {
i += 1; }

21. MIS 324 -- Professor Sandvig
11/7/2018
Summary
C# modern object oriented programing language
Relatively easy to use
Managed code
C-like syntax (similar to PHP, JavaScript, C, C++)
Strongly typed
Explicitly convert data types
Pick up syntax quickly
Visual Studio big help