Simple C Programs

1
Simple C Programs

• ELEC 206
• Computer Applications for Electrical Engineers
• Dr. Ron Hayne

2
Program Structure

• Object-Based Programming
• Program Structure
• Dev-C

3
Object-Based Programming

• Object-Oriented Programming
• Identify the data requirements of the problem
• How the data will be used in the program
• Abstract Data Types
• Class
• Inheritance

4
C Program

• /-----------------------------------------------
  /
• / Program chapter1_1
  /
• /
  /
• / This program computes the distance between
  /
• / two points
  /
• include ltiostreamgt
• include ltcmathgt
• using namespace std

5
C Program

• int main()
• // Declare and initialize objects
• double x1(1), y1(3), x2(4), y2(7),
• side1, side2, distance
• // Compute sides of right triangle
• side1 x2 - x1
• side2 y2 - y1
• distance sqrt(side1 side1 side2 side2)

6
C Program

• // Print distance
• cout ltlt "The distance between the two points is
  "
• ltlt distance ltlt endl
• // Windows friendly exit
• system("PAUSE")
• return 0
• /----------------------------------------------/
  

7
Program Structure

• Comments
• /-----------------------------------------------
  /
• / Program chapter1_1
  /
• // Declare and initialize objects
• Preprocessor Directives
• include ltiostreamgt
• include ltcmathgt
• Using Directive
• using namespace std

8
Program Structure

• Main Function
• int main()
• Declarations
• object types
• initial values
• // Declare and initialize objects
• double x1(1), y1(3), x2(4), y2(7),
• side1, side2, distance

9
Program Structure

• Statements
• // Compute sides of right triangle
• side1 x2 - x1
• side2 y2 - y1
• distance sqrt(side1 side1 side2 side2)
• // Print distance
• cout ltlt "The distance between the two points is
  "
• ltlt distance ltlt endl
• Return
• return 0

10
General Program Structure

• preprocessing directives
• int main()
• declarations
• statements

11
Dev-C

• Bloodshed Software
• http//www.bloodshed.net/dev/devcpp.html
• Dev-C 5.0 beta 9.2 (4.9.9.2) (9.0 MB) with
  Mingw/GCC 3.4.2
• Download from
• SourceForge

12
Dev-C
13
Windows Friendly Exit

• // Windows friendly exit
• system("PAUSE")
• return 0

14
Summary

• Object-Based Programming
• Program Structure
• Dev-C

15
Simple C

• Constants and Variables
• C Operators
• Standard Input and Output

16
Constants and Variables

• Objects
• Constants
• Specific values
• Variables
• Memory locations
• Identifiers
• Begin with alphabetic character
• Lowercase or uppercase letters (case sensitive)
• Can contain digits (not first character)
• Cannot be a keyword

17
Scientific Notation

• Floating-Point
• 2.5, -0.004, 15.0
• Scientific Notation
• 25.6 2.56 x 101
• -0.004 -4.0 x 10-3
• Exponential Notation
• 25.6 2.56e1
• -0.004 -4.0e-3

• Mantissa
• Precision
• Example
• Exponent
• Range

18
Numeric Data Types

• Integers
• short
• int
• long
• Floating-Point
• float
• double
• long double

19
Boolean Data Type

• Example
• bool error(false), status(true)
• cout ltlt error ltlt endl ltlt status
• Program Output

0 1
20
Character Data Type

• ASCII
• Appendix B
• 7-bit binary
• Character Constant
• Single quotes
• 'A', 'b', '3'
• Can be interpreted as character or integer
• '3' ! 3

21
String Data

• String Constant
• Sequence of characters
• Double quotes
• "Fred", "C17"
• String Objects
• string class

22
String Class

• /-----------------------------------------------
  /
• / This program prints a greeting
  /
• / using the string class.
  /
• include ltiostreamgt
• include ltstringgt // Required for string class
• using namespace std

23
String Class

• int main()
• // Declare and initialize two string objects.
• string salutation("Hello"), name("Jane Doe")
• // Output greeting.
• cout ltlt salutation ltlt ' '
• ltlt name ltlt '!' ltlt endl
• // Exit program.
• return 0

Hello Jane Doe!
24
Symbolic Constants

• Const
• Declared and initialized
• Cannot be changed within the program
• const double PI acos(-1.0)
• const double LightSpeed 2.99792e08

25
C Opeartors

• Assignment Operator
• identifier expression
• Expression
• Constant, Object, Result of an Operation
• double sum(10.5)
• int x1(3)
• char ch('a')

double sum int x1 char ch sum 10.5 x1
3 ch 'a'
26
Assignment Operator

• Multiple Assignments
• x y z 0
• Type Conversion
• long double
• double
• float
• long integer
• integer
• short integer

27
Arithmetic Operators

• Unary Operators
• Positive
• Negative -
• Binary Operators
• Multiplication
• Division /
• Modulus
• Addition
• Subtraction -

28
Mixed Operations

• Operation between values of different types
• Value of lower type promoted
• Cast Operator
• (type)
• Examples

29
Expressions

• Distance x0 v0t at2
• double distance, x0, v0, a, t
• distance x0 v0t att
• Tension ?

30
Increment and Decrement

• Unary Operators
• Increment
• Decrement --
• Prefix count
• Postfix count--
• Examples

31
Abbreviated Assignment

• Abbreviated Assignment Operators
• x x 3 x 3
• y y 2 y 2
• Lowest Precedence (evaluate last)
• a (b (c d))
• a (b b (c d))
• b b (c d)
• a b

32
Standard Output

• Standard Output
• include ltiostreamgt
• cout ltlt "Hello " ltlt name
• Stream Manipulators
• include ltiomanipgt
• setprecision(n), fixed, scientific
• setw(n), left, right, setfill(ch)
• dec, oct, hex
• endl

33
Standard Output

• /-----------------------------------------------
  /
• / Program chapter2_4
  /
• /
  /
• / This program computes area of a circle.
  /
• include ltiostreamgt
• include ltiomanipgt
• include ltcmathgt
• using namespace std

34
Standard Output

• const double PIacos(-1.0)
• int main()
• // Declare and initialize objects.
  
• double radius(4.6777), area
• // Compute area
• area PIradiusradius

35
Standard Output

• // Output results
• cout ltlt setprecision(4)
• ltlt "The radius of the circle is "
• ltlt setw(10) ltlt radius ltlt " centimeters"
• ltlt endl
• cout ltlt scientific
• ltlt "The area of the circle is " ltlt
  setw(12)
• ltlt area ltlt " square centimeters" ltlt endl

36
Standard Input

• Standard Input
• include ltiostreamgt
• cin gtgt var1 gtgt var2 gtgt var3
• Whitespace used as delimiters
• blanks, tabs, newlines
• Values must be compatible with data type of
  objects
• Stream Manipulators
• include ltiomanipgt
• skipws, noskipws

37
Summary

• Constants and Variables
• C Operators
• Standard Input and Output

38
Problem Solving

• Basic Functions
• Numerical Technique
• Linear Interpolation
• Problem Solving Applied
• Wind-Tunnel Data Analysis

39
Basic Functions

• Basic Math Functions
• include ltcmathgt
• Arguments are type double
• Elementary Math Functions
• fabs(x), abs(n)
• sqrt(x), pow(x,y)
• ceil(x), floor(x)
• exp(x), log(x), log10(x)

40
Basic Functions

• Trigonometric Functions
• Angles in radians (180 degrees p radians)
• sin(x), cos(x), tan(x)
• asin(x), acos(x), atan(x), atan2(y,x)
• const double PI acos(-1.0)
• double angle_deg, angle_rad
• angle_deg angle_rad(180/PI)
• angle_rad angle_deg(PI/180)

41
Practice

• velocity sqrt(pow(v0,2) 2a(x - x0))

42
Other Functions

• Hyperbolic Functions
• sinh(x), cosh(x), tanh(x)
• Character Functions
• include ltcctypegt
• toupper(ch), tolower(ch)
• isdigit(ch), isupper(ch), islower(ch)
• isspace(ch), ispunct(ch)

43
Interpolation

• Use data points to determine estimates of a
  function f(x) for values of x that were not part
  of the original set of data
• Cubic-spline Interpolation
• Third-degree polynomial
• Linear Interpolation
• Straight line
• a lt b lt c

44
Example

• Data Set

• Estimate the tempat 2.6s

45
Problem Solving Applied

• Wind-Tunnel Data Analysis
• Problem Statement
• Use linear interpolation to compute a new
  coefficient of lift for a specified flight-path
  angle
• Input/Output Description

Data Point (a, f(a))
New Coefficient f(b)
Data Point (c, f(c))
New Angle (b)
46
Problem Solving Applied

• Hand Example
• Estimate coefficient of lift at 8.7 degrees
• Algorithm Development
• Read coordinates of adjacent points
• Read new angle
• Compute new coefficient
• Print new coefficient

47
Problem Solving Applied

• /-----------------------------------------------
  /
• / Program chapter2_5
  /
• /
  /
• / This program uses linear interpolation to
  /
• / compute the coefficient of lift for an
  angle./
• include ltiostreamgt
• include ltiomanipgt
• include ltcmathgt
• using namespace std
• int main()

48
Problem Solving Applied

• // Declare objects
• double a, f_a, b, f_b, c, f_c
• // Get user input from the keyboard.
• cout ltlt "Use degrees for all angle measurements.
  \n"
• cout ltlt "Enter first angle and lift coefficient
  \n"
• cin gtgt a gtgt f_a
• cout ltlt "Enter second angle and lift coefficient
  \n"
• cin gtgt c gtgt f_c
• cout ltlt "Enter new angle \n"
• cin gtgt b

49
Problem Solving Applied

• // Use linear interpolation to compute new lift.
  
• f_b f_a (b-a)/(c-a)(f_c - f_a)
• // Print new lift value.
• cout ltlt fixed ltlt setprecision(3)
• cout ltlt "New lift coefficient " ltlt f_b ltlt endl
• // Windows friendly exit
• system("PAUSE")
• return 0

50
Problem Solving Applied

• Testing

51
Summary

• Basic Functions
• Numerical Technique
• Linear Interpolation
• Problem Solving Applied
• Wind-Tunnel Data Analysis
• End of Chapter Summary
• C Statements
• Style Notes
• Debugging Notes