Introduction to Programming

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Introduction to Programming

• Lecture 33

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In Todays Lecture

• Operator overloading
• Assignment operator
• A this pointer
• Operator over loading using this pointer
• Conversion function

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Assignment Operator
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a b
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Member Wise Assignment
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Member Wise Copy
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Example

• class String
• char buf 100
• public
• String ( )
• String ( )
• ...

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Example

• main ( )
• String s1 ( This is a test )
• String s2
• s2 s1

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s2 s1
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Example

• void String operator ( String s1 )
• delete buf
• buf new char s1.buf 1
• strcpy ( buf , s1.buf )

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Assignment Operator

• int i , j , k
• i 5
• j 10
• k 15
• i j
• k i

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i j k k i j
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k i j
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this pointer
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this pointer

• buf
• this -gt buf
• ( this ).buf

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• int i
• i i // nothing happens

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• String s 1000 This is a Test
• s s

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Self Assignment
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Example

• main ( )
• String s , sPtr
• sPtr s
• .
• .
• .
• s sPtr

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Example

• void String operator ( String other )
• if ( this other )
• return
• --------

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Example

• String String operator ( String other )
• if ( this other )
• return this
• delete buf
• buf new char other.length 1
• strcpy ( buf , other.buf )
• return this

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s3 s2 s1
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cout ltlt a ltlt b ltlt c
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Example

• Date d1 , d2
• d2 d1
• d2 d1 1

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Example

• Date date1 , date2
• date2 date1 1
• date2 date1

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Example

• main ( )
• int i
• float x
• x i
• i x

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Example

• main ( )
• Date d
• int i
• d i

?
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Example

• main ( )
• int i
• float x
• x ( float ) i

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Conversion Function
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• Date ( )
• // body of function

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• double x 1 / 3 Output 0.33333
• x 3 Output 0.99999

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Common Business Oriented Language