Project 7
- Write a Fraction class that implements a representation of a fraction, where each instance consists of a numerator and a denominator. Overload addition, subtraction, and multiplication for this class. Write a method to format each fraction in the form
5/7
For your first attempt it is not necessary to reduce the fraction, i.e. it is acceptable to have fractions like 6/8. Be sure to check for division by zero in your division procedure.
-
Add a reduce method that finds the least common multiple to obtain the lowest common denominatorand reduce the fraction.
-
Set fractions with a denominator of 0 to 0/0 (this is arbitrary).
-
Write a driver to test all your procedures.
Example solution
module Fractions
implicit none
private
public :: Fraction
type Fraction
private
integer :: num, denom
contains
private
procedure adder
procedure subber
procedure multer
procedure divver
procedure copier
procedure, public :: reduce
procedure, public :: print=>printer
generic, public :: operator(+) => adder
generic, public :: operator(-) => subber
generic, public :: operator(*) => multer
generic, public :: operator(/) => divver
generic, public :: assignment(=) => copier
end type
interface Fraction
module procedure init
end interface
contains
!Helpers
integer function gcd(num, denom)
integer, intent(in) :: num, denom
integer :: den, temp
gcd=num
den=denom
do while ( den /= 0 )
temp=den
den=modulo(gcd,den)
gcd=temp
end do
end function
type(Fraction) function init(num,denom)
integer, intent(in) :: num, denom
if ( denom /= 0 ) then
init%num=num
init%denom=denom
else
init%num=0
init%denom=0
endif
end function init
!Methods
subroutine reduce(self)
class(Fraction) :: self
integer :: g_c_d
g_c_d=gcd(self%num,self%denom)
self%num =self%num/g_c_d
self%denom=self%denom/g_c_d
end subroutine reduce
type(Fraction) function adder(self,f)
class(Fraction), intent(in) :: self
type(Fraction), intent(in) :: f
integer :: num, denom
if ( self%denom .ne. 0 .and. f%denom .ne. 0 ) then
num=self%num*f%denom+f%num*self%denom
denom=self%denom*f%denom
adder=Fraction(num,denom)
call adder%reduce()
else
adder=Fraction(0,0)
endif
end function adder
type(Fraction) function subber(self,f)
class(Fraction), intent(in) :: self
type(Fraction), intent(in) :: f
integer :: num, denom
if ( self%denom .ne. 0 .and. f%denom .ne. 0 ) then
num=self%num*f%denom-f%num*self%denom
denom=self%denom*f%denom
subber=Fraction(num,denom)
call subber%reduce()
else
subber=Fraction(0,0)
endif
end function subber
type(Fraction) function multer(self,f)
class(Fraction), intent(in) :: self
type(Fraction), intent(in) :: f
integer :: num, denom
if ( self%denom .ne. 0 .and. f%denom .ne. 0 ) then
denom=self%denom*f%denom
num=self%num*f%num
multer=Fraction(num,denom)
call multer%reduce()
else
multer=Fraction(0,0)
endif
end function multer
type(Fraction) function divver(self,f)
class(Fraction), intent(in) :: self
type(Fraction), intent(in) :: f
integer :: num, denom
if ( self%denom .ne. 0 .and. f%denom .ne. 0 ) then
denom=self%denom*f%num
num=self%num*f%denom
divver=Fraction(num,denom)
call divver%reduce()
else
divver=Fraction(0,0)
endif
end function divver
subroutine copier(new,old)
class(Fraction), intent(out) :: new
class(Fraction), intent(in) :: old
new%num=old%num
new%denom=old%denom
end subroutine copier
subroutine printer(self,iunit)
class(Fraction), intent(in) :: self
integer, intent(in) :: iunit
write(iunit,'(i0,a,i0)') self%num,'/',self%denom
end subroutine printer
end module Fractions