1. .Net Programming with C#
Haiming Chen
Department of Computer Science
Ningbo University
Fall Semester ,
Course 106F22A01

2. Outline Variables and constants (types) Operators Expression
Flow of program
Sequence
Selection
Loop

3. Arithmetic operation Operator Description Expression + Add
For strings, join
opt1 + opt2 -
Subtract
opt1 - opt2 *
Multiple
opt1 * opt2 /
Divide
opt1 / opt2 %
Mode
opt1 % opt2 ++
Add 1
opt++ or ++opt --
Minus 1
opt– or --opt ~
Reverse each bit
~opt

4. Condition operation operator Description Expression
? :
If the result of expression is true,
then run operand1,
otherwise run operand2
<Relationship expression or logic expression> ?
operand1:
operand2

5. Relationship operation
Operator
Description
Expression
>
Larger than
opt1 > opt2
<
Less than
opt1 < opt2
>=
No less than
opt1 >= opt2
<=
No larger than
opt1 <= opt2 ==
Equal
opt1 == opt2 !=
No equal
opt1 != opt2
Result is True or False

6. Logic operation opt, opt1, opt2 are boolean Result is True or False
Operator
Description
Expression
&&
and
opt1 && opt2 || or
opt1 || opt2 !
not
! opt
opt, opt1, opt2 are boolean
Result is True or False

7. Set operation operator format expression equivalent result（ X = 10） =
var = exp
X=x+2
X=x+12 12 +=
var = exp1 + exp2
X+= 2
X=X+2 -=
var = exp1 - exp2
X-= 2
X=X-2 8 *=
var = exp1 * exp2
X*= 2
X=X*2 20 /=
var = exp1 / exp2
X/= 2
X=X/2 5 %=
var = exp1 % exp2
X%= 2
X=X%2

8. Change priority of operation
Special operation
Type
operation
description
Expression
Member access .
Access data member or methods of a class or an object
class.member
object.member
Note: data type can be seen as class name
Type conversion ()
Convert type of variable
(type_name) opt
1+2*3/5
(1+2)+2*3/5
Change priority of operation

9. Example
int i=21, j=-1;
bool blVar = i>1 && j<0;

10. Priority Priority Operator 1 ( ) 2 ++/-- 3 * / % 4 + - 5 < <=
>
>= 6 == != 7
&& 8 || 9
= += *=
/= %= -=

11. Example 1
X==0 y
X/2
X!=0

12. condition can only be boolean
Selective Structure
condition can only be boolean
if … else
if (<condition>) {
<statement 1> }
else
<statement 2>
if (<condition>) {
<statement 1> }
else if
<statement 2>
else
<statement 3>

13. expression can only be boolean, char, int, string
Selective Structure
switch…case
expression can only be boolean, char, int, string
switch (<expression>) {
case constant1: …
break;
case constant2:
case constant3: }

14. Continue without judging the condition
Loop structure
while (<condition>) {
<statements> }
Break
Go out from the loop do {
<statements>
} while (<condition>)
Continue
Continue without judging the condition

15. Loop structure
for (initialize value of variable; condition; increase or decrease variable) {
//statement }
foreach (type var in array or string) {
//statement }

16. Quiz
Read a line from the console, and count the numbers of letters, digits, respectively.
1123abcd48
Number of letters: 4
Number of digits: 6
char.IsChar(var) //
char.IsDigit(var) //