Introduction to Programming

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Introduction to Programming

• Lecture 37

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Operator Overloading
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Stream Insertion / Extraction
Operator Overloading
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• int i
• cin gtgt i

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• int a , b , c
• a b c

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• cin gtgt i gtgt j

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Friend Function
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Member Operators
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Object.dataObject.function ( )
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Stream Insertion Operator
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• int i 5 , j 10 , k 15
• cout ltlt i ltlt j ltlt k

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ostream operator ltlt ( ostream output ,
vehicle A )
Return type Reference to the output stream
Operator


Reference to the output stream
Object of the class
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Definition

• ostream operator ltlt ( ostream output ,
  vehicle d )
• outputltlt d.seats
• outputltltd.tires
• -------
• return output

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• cout ltlt d

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cout ltlt The description of the vehicle is \n ltlt
d
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Example

• class Matrix
• private
•           int rows , cols           int
  elements 3 3
• public
• Matrix ( int rows 3 , int cols 3 )
•   friend ostream operator ltlt ( ostream
  output , Matrix m )

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Example

• ostream operator ltlt ( ostream output , Matrix
  m )
• for ( int i 0 i lt m.rows i )   
          for ( int j 0 j lt m.cols j
  )                  output ltlt m.elements i
  j                 return output

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• int i
• cin gtgt i

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• Matrix x
• cin gtgt x

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Example

• class Matrix
• private
• int rows, cols
• int elements 3 3
• public
• Matrix ( int rows 3 , int cols 3 )
• friend ostream operator ltlt ( ostream output
  , Matrix m )
•   friend istream operator gtgt ( istream
  input , Matrix m )

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Example

• istream operator gtgt ( istream input , Matrix
  m ) coutltlt Please enter the values of
  the matrix
•     for ( int i 0 i lt m.rows i )   
          for ( int j 0 j lt m.cols j
  )                  cout ltlt Please enter
  the values of elements ltlt i ltlt , ltlt j
• input gtgt m.elements i j
                  return input

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Example

• Matrix m
• m.getMatrix ( )
• m.displayMatrix ( )

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Example

• Matrix m
• cin gtgt m
• cout ltlt m