Friday, December 08, 2006

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Friday, December 08, 2006

• Experience is something you don't get until just
  after you need it.
• - Olivier

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• Numeric data types

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Declarations and Initialization

double dx dx3.5 OR double dx3.5
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Declarations and Initialization

//(comma separated) double a, b, c5.6, d
double r1, r2, r3 //(white spaces
ignored) /All declarations and statements must
end with semicolon /
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• int big980000
• short small
• coutltlt"big"ltltbigltltendl
• smallbig //don't do this
• coutltlt"small"ltltsmallltltendl

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• int big980000
• short small
• coutltlt"big"ltltbigltltendl
• smallbig //don't do this
• coutltlt"small"ltltsmallltltendl
• big980000
• small-3040

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• short small 980000
• cout ltlt small ltlt endl
• -3040

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Character Data

• Each character corresponds to a binary code
• Most commonly use binary codes are ASCII
  (American Standard Code for Information
  Interchange)
• Character ASCII Code Integer Equivalent
• 0100101 37
• 3 0110011 51
• A 1000001 65
• a 1100001 97
• b 1100010 98
• c 1100011 99

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Arithmetic Operators

• Addition
• Subtraction -
• Multiplication
• Division /
• Modulus

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Arithmetic Operators

• Addition
• Subtraction -
• Multiplication
• Division /
• Modulus
• Modulus returns remainder of division between two
  integers
• cannot be used on float or double

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• Example
• 5 2 evaluates to ?
• 10 2 evaluates to ?

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• Example
• 5 2 evaluates to 1
• 10 2 evaluates to 0

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Arithmetic Operators

• Division between two integers results in an
  integer.
• The result is truncated, not rounded

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Modulo operation

• 17 / 5 evaluates to
• 17 5 evaluates to

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Modulo operation

• 17 / 5 evaluates to 3.
• 17 5 evaluates to 2.

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• Example
• 5/3 evaluates to ?
• 3/6 evaluates to ?

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• Example
• 5/3 evaluates to 1
• 3/6 evaluates to 0

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Priority of Operators

• Parentheses Inner most first
• Unary operators Right to left
• ( -)
• Binary operators Left to right
• ( / )
• Binary operators Left to right
• ( -)

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Precedence

• Order of mathematical operations is
  important.Examples
• (32)4 54 20
• 3(24) 3 8 11
• and / evaluated before and -Example 324
  evaluated as 3(24)

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Precedence

• If precedence is equal, then evaluate from left
  to right.Examples
• 325 5 5 10
• 32/5 6/5 1
• Parentheses enforce evaluation orderExample
  (32)4 54 20

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Unary operators , -

• Unary operators , -
• -3, 17 allowed
• Example 4(-3) -12

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Assignment Operators
assignment operator Compound Assignment
Operators operator example equivalent statement
x2 xx2 - x-2 xx-2 xy x
xy / x/y xx/y
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Example x 4 x 5
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Example x 4 x 5 // x 20
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Arithmetic Operators

• unary operators
• auto increment
• post increment x
• pre increment x
• auto decrement - -
• post decrement x- -
• pre decrement - -x

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• x is executed after it is used
• x 7
• y x
• x is also equivalent to x x1
• x executed before it is used
• x 7
• y x
• --x is equivalent to x x-1
• -- works just like , but with subtraction
  instead of addition

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• x is executed after it is used
• x 7
• y x // x 8, y 7
• x is also equivalent to x x1
• x executed before it is used
• x 7
• y x // x 8, y 8
• --x is equivalent to x x-1
• -- works just like , but with subtraction
  instead of addition

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Shortcuts

• n equivalent to n n 1read as "add 1 to n"
  
• n-- equivalent to n n - 1read as "subtract 1
  from n"
• s n equivalent to s s n read as "add n
  to s"
• s - n equivalent to s s - nread as "subtract
  n from s