AERO 220 Introduction to Aerospace Engineering Computation

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AERO 220 Introduction to Aerospace Engineering
Computation
Meetings Time Tuesdays and Thursdays,1110 AM
1225 PM Place SSC 102 B http//imechanica.org/n
ode/6727 9/10/09
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Objectives

• Variables
• Cs built-in integer type char and bool
• Cs built-in floating point types (float,
  double and long double)
• The cfloat file
• Numeric constants of floating-point type
• Arithmetic operators and type conversion

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The char and bool types

• char type is to store characters, such as letters
  and digits
• Number code for characters
• char type is another integer type, typically
  smaller than short
• bool variables represent either true or false
• bool isready true
• int ans true // ans assigned 1
• int promise false // promise assigned 0

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The ASCII Character set
Extended ASCII Character Chart
American Standard Code for Information
Interchange (ASCII) See appendix c of the test
book
http//www.rtis.com/nat/user/toolbox/oldmacs/MacEu
doraManual/man151172.GIF
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The const qualifier

• Symbolic name for constants
• const int MONTHS 12 // MONTHS is the symbolic
  constant for 12
• General form for creating a constant
• const type name value
• const int toes // value of toes undefined at
  this point
• toes 10 // too late!

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Floating-point number

• Represents number with a fractional part
• For example 2.5, 3.14159 and 122245.6567
• Writing floating point number
• Standard decimal-point notation
• 12.34
• 0.003
• 8.0
• E notation
• 5.37E16 ( 5.37x1016)
• 2.53e8 (can use E or e)
• 7E5 (same as 7.0E5, is a floating point
  number even if no decimal point is used)
• 8.33e-4 (exponent can be negative)

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Floating-point number and floating point types

• 3.45E6 3.4x106
• 3.45 is called the mantissa
• 6 is called the exponent
• Floating point types
• float (at least 32 bits)
• double (at least 48 bits)
• long double (at least 48 bits)
• Always use double!
• cfloat header file

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Floating point constants

• 1.234f // a float
• 3.45e5 //a double
• 2.345E5 // a double
• 4.56L // a long double (dont use lower case L )

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C Arithmetic operators

• C a b
• a b is an expression
• a and b are operands, is the operator
• Five basic operators
• The operator (add)
• The operator (subtract)
• The operator (multiplication)
• The / operator (division)
• The operator (modulus operator), produces the
  reminder of dividing the first by the second
  operands. E.g., 19 6 is 1. Operands must be
  integers.

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Operator precedence and associativity

• int flyingpings 3 4 5 // flyingpings 23
  or 35?
• float logs 120 / 4 5 // longs 150 or 6?
• int dues 20 5 24 6

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Modulus operator
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Type conversion

• Assigning a value to a type with a greater range
  usually poses no problem
• long so_long
• short thirty
• So_long thirty // assigning a short to a long

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Type conversion
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Type casts

• General form
• typeName (value)
• Examples
• int number
• number int (19.99) int (11.99)