Operator

1
Operator
2
Assignation ().

• The assignation operator serves to assign a value
  to a variable.a 5
• It is necessary to emphasize that the assignation
  operation always takes place from right to left
  and never at the inverse.a b

3
Example

• int a, b // a? b?
• a 10 // a10 b?
• b 4 // a10 b4
• a b // a4 b4
• b 7 // a4 b7

4
Compound assignation operators

• (, -, , /, , gtgt, ltlt, , , )

5
Example

• value increase is equivalent to value value
  increase
• a - 5 is equivalent to a a - 5
• a / b is equivalent to a a / b
• price units 1 is equivalent to price
  price (units 1)

6
Increase and decrease.

• Another example of saving language when writing
  code are the increase operator () and the
  decrease operator (--). They increase or reduce
  by 1 the value stored in a variable. They are
  equivalent to 1 and to -1, respectively.
  Thus a a1 aa1
• are all equivalent in its functionality the
  three increase by 1 the value of a.

7
Arithmetic operators( , -, , /, )

• The five arithmetical operations supported by the
  language are
• addition
• -subtraction
• multiplication
• /division
• module

8
Relational Operator

• ( , !, gt, lt, gt, lt )

9
Relational operators

• Equal
• !Different
• gtGreater than
• ltLess than
• gtGreater or equal than
• ltLess or equal than

10
Example

• (7 5)would return false.
• (5 gt 4)would return true.
• (3 ! 2)would return true.
• (6 gt 6)would return true.
• (5 lt 5)would return false.

11
Example 2

• Suppose that a2, b3 and c6
• (a 5)would return false.
• (ab gt c)would return true since (23 gt 6) is
  it.
• (b4 gt ac)would return false since (34 gt 26)
  is it.
• ((b2) a)would return true.

12
Logical Operator

• ( !, , ).

13
NOT Logic operators

• !(5 5)returns false because the expression at
  its right (5 5) would be true.
• !(6 lt 4)returns true because (6 lt 4) would be
  false.
• !truereturns false.
• !falsereturns true.

14
Logic operators and
FirstOperanda SecondOperandb resulta b resulta b
True True True True
True False False True
False True False True
False False False False
15
Example

• ( (5 5) (3 gt 6) ) returns false ( true
  false ).
• ( (5 5) (3 gt 6)) returns true ( true
  false ).

16
Conditional operator ( ? )

• The conditional operator evaluates an expression
  and returns a different value according to the
  evaluated expression, depending on whether it is
  true or false.
• Its format is
• condition ? result1 result2
• if condition is true the expression will return
  result1, if not it will return result2.

17
Example

• 75 ? 4 3  returns 3 since 7 is not equal to
  5.
• 752 ? 4 3  returns 4 since 7 is equal to
  52.
• 5gt3 ? a b  returns a, since 5 is greater than
  3.
• agtb ? a b  returns the greater one, a or b.

18

• / Program COMPARES.C /
• int main() / This file will illustrate logical
  compares /
• int x 11, y 11, z 11
• char a 40, b 40, c 40
• float r 12.987, s 12.987, t 12.987
• / First group of
  compare statements /
• if (x y) z -13 / This will set z
  -13 /
• if (x gt z) a 'A' / This will set a 65
  /
• if (!(x gt z)) a 'B' / This will change
  nothing /
• if (b lt c) r 0.0 / This will set r
  0.0 /
• if (r ! s) t c/2 / This will set t 20
  /
• / Second group of
  compare statements /
• if (x (r ! s)) z 1000 / This will set x
  some positive
• number and z
  1000 /

19

• // Filename RELAT1ST.CPP
• // Prints the results of several relational
  operations
• include ltiostream.hgt
• void main()
• int high 45
• int low 10
• int middle 25
• int answer
• answer high gt low
• cout ltlt "High gt low is " ltlt answer ltlt endl
• answer low gt high
• cout ltlt "Low gt high is " ltlt answer ltlt endl
• answer middle middle
• cout ltlt "Middle middle is " ltlt answer ltlt endl

20
Output

• High gt low is 1
• Low gt high is 0
• Middle middle is 1
• High gt middle is 1
• Middle lt low is 0
• Bonus relation 0 0 is 1