Bài giảng lập trình c 2010 chương 1 1 đh công nghệ đồng nai

Operators Implicitly Typed Local Variables Incrementing & Decrementing Variables... -Comments 1 -A Statement is a command that performs an action, -Comments use to explain for your Co

Operators and Expressions

Operators

Implicitly Typed Local

Variables

Incrementing &

Decrementing Variables

-Comments

1

-A Statement is a command that performs an action,

-Comments use to explain for your Coding

How to write comments???

See next slide…

//Comment 1

/*

*Comment 2

*/

/*Comment 3*/

/// <summary>

/// </summary>

/// <param name=“a"></param>

/// <param name=“b"></param>

private void func1(int a,float b)

2

Identifiers are names use to identify the elements in

Syntax Rules:

-Only use letter, digit, underscore -An identifier must start with a letter or an underscore -C# is a case –sensitive : nTest and ntest is different identifier

abstract do in protected true

dynamic join set

from let value

group partial where

into select yield

Identifying Keywords

- A variable is storage location that holds a value It as a box in the Computer’s memory holding temporary

information.

-To easy coding:

+Don’t start an identifier with underscore

+Start name with lower case +….

Variables

3

How to declare variables?

Data_type NameVariable;

string strFullName;

float fValue=0,fResult;

Data Type Description Size(bits) Range Example

int Whole numbers 32 –231 through 231 – 1 int nSize;

(bigger range) 64 –263 through 263 – 1 long lSize;

float Floating-point numbers 32 ±1.5 × 1045 through ±3.4 × 1038 float fDelta;

double

Double-precision (more accurate) floating-point numbers

64 ±5.0 × 10−324 through ±1.7 × 10308 double dDelta;

string Sequence of characters 16 bits per character Not applicable string strName;

char Single character 16 0 through 216 – 1 char chrAns;

You should initialize value for variable

int nSize=0;

String strName=“”;

Arithmetic

Operators

5

113 and 114 are the operands

Not all operators are applicable to all data

types

Example:

statements:

Console.WriteLine(“Tý” - “Tèo”);

How to convert from String to Number Format ?

int nValue=System Int32 Parse("113");

double dValue = System.Double.Parse("3.5");

Datatype vName=System DataTypeObject Parse(“ string ”);

Incrementing &

Decrementing Variables

6

X++

Postfix increment

++X

Prefix increment

X Postfix decrement

X

Prefix decrement

Implicitly Typed Local

Variables 7

var sAny;

Error: Implicitly-typed local variables must be initialized

var number1=1;

var strAny=“tèo”;

END