Computer Notes - Stream Insertion operator

1
Stream Insertion operator
http//ecomputernotes.com
2
Stream Insertion operator

• Often we need to display the data on the screen
• Example
• int i1, j2
• cout ltlt i ltlt i ltlt \n
• Cout ltlt j ltlt j ltlt \n

http//ecomputernotes.com
3
Stream Insertion operator

• Complex c1
• cout ltlt c1
• cout ltlt c1 ltlt 2
• // Compiler error binary 'ltlt' no operator //
  defined which takes a right-hand //
  operand of type class Complex

4
Stream Insertion operator

• class Complex
• public
• void operator ltlt (const
• Complex rhs)

http//ecomputernotes.com
5
Stream Insertion operator

• int main()
• Complex c1
• cout ltlt c1 // Error
• c1 ltlt cout
• c1 ltlt cout ltlt 2 // Error
• return 0

http//ecomputernotes.com
6
Stream Insertion operator

• class Complex
• public
• void operator ltlt (ostream )

http//ecomputernotes.com
7
Stream Insertion operator

• void Complexoperator ltlt (ostream os)
• os ltlt ( ltlt real
• ltlt , ltlt img ltlt )

http//ecomputernotes.com
8
Stream Insertion operator

• class Complex
• ...
• friend ostream operator ltlt (ostream os, const
  Complex c)

Note return type is NOT const
Note this object is NOT const
http//ecomputernotes.com
9
Stream Insertion operator

• // we want the output as (real, img)
• ostream operator ltlt (ostream os, const
  Complex c)
• os ltlt ( ltlt c.real
• ltlt ,
• ltlt c.img ltlt )
• return os

http//ecomputernotes.com
10
Stream Insertion operator

• Complex c1(1.01, 20.1), c2(0.01, 12.0)
• cout ltlt c1 ltlt endl ltlt c2

http//ecomputernotes.com
11
Stream Insertion operator

• Output
• ( 1.01 , 20.1 )
• ( 0.01 , 12.0 )

http//ecomputernotes.com
12
Stream Insertion operator

• cout ltlt c1 ltlt c2
• is equivalent to
• operatorltlt(
• operatorltlt(cout,c1),c2)

http//ecomputernotes.com
13
Stream Extraction Operator

• Overloading gtgt operator
• class Complex
• ...
• friend istream operator gtgt (istream i,
  Complex c)

Note this object is NOT const
14
Stream Extraction Operator

• istream operator ltlt (istream in, Complex
  c)
• in gtgt c.real
• in gtgt c.img
• return in

http//ecomputernotes.com
15
Stream Extraction Operator

• Main Program
• Complex c1(1.01, 20.1)
• cin gtgt c1
• // suppose we entered // 1.0025 for c1.real
  and // 0.0241 for c1.img
• cout ltlt c1

http//ecomputernotes.com
16
Stream Extraction Operator

• Output
• ( 1.0025 , 0.0241 )

http//ecomputernotes.com
17
Other Binary operators

• Overloading comparison operators
• class Complex
• public
• bool operator (const Complex c)
• //friend bool operator (const //Complex c1,
  const Complex c2)
• bool operator ! (const Complex c)
• //friend bool operator ! (const //Complex c1,
  const Complex c2)

18
Other Binary operators

• bool Complexoperator (const Complex c)
• if((real c.real)
• (img c.img))
• return true
• else
• return false

http//ecomputernotes.com
19
Other Binary operators

• bool operator (const
• Complex lhs, const Complex rhs)
• if((lhs.real rhs.real)
• (lhs.img rhs.img))
• return true
• else
• return false

http//ecomputernotes.com
20
Other Binary operators

• bool Complexoperator !(const Complex c)
• if((real ! c.real)
• (img ! c.img))
• return true
• else
• return false

http//ecomputernotes.com