100 Days of Code Log R1D2

Today I had continued with Fortran for Scientific Computing and learned about

• Character datatype
• Logical datatype and operators
• Conditional Statements

Character Datatypes

The character dataypes are declared as either a single character or as an array of particular length.

1
2

character :: c
character(len=5) :: str

Two main points about strings are that,

• if the length of string input is less than specified, the remaining is filled by space.
• If it greater than the specified length, only the specified length is read and rest is discarded.

Also, I learnt about functions such achar, iachar, trim, len_trim and so on.

Logical statements

The logical statements are verbose and hence it is very easy to read how they work. In the following code, read .eqv. as “equivalent” and .neqv. as not equivalent. The rest will be easy to understand.

1
2
3
4
5
6

logical function is_it_leap_year(year)
	
	integer :: year
	is_it_leap_year = (mod(year, 400)==0) .or. (mod(year, 4)==0) .and. .not. (mod(year, 100)==0)

end function is_it_leap_year

Conditional Statements

The fortran code has two ways of having if statements

Multiline

1
2
3

if (x< 3) then
	x = x+3
end if

Inline (logical if)

1

if (x<3) x = x+3

Iterations

The iterations are carried through either

1
2
3
4
5

! do loops

do i = 1, 11, 2 ! 1 - start; 11 - end; 2 - step size
	print *, i, i**2
end do

or the

1
2
3
4
5
6

! while loops
integer :: i = 0
do while (i < 10)
	print *, i, i**2
	i = i + 2
end do

I also attempted the quizzes which gave insights to the various little things by which fotran may differ from, say, python.