Declarations in Fortran

Four typed variables for the lighthouse log, declared before any statement runs.

program declarations
    ! implicit none turns off the 1950s i-through-n typing rules.
    implicit none
    integer :: lamp_turns = 148
    real :: oil_gallons = 6.5
    character(len=12) :: station = "Gull Rock"
    logical :: storm_watch = .true.

    print *, "Station: ", station
    print *, "Turns tonight: ", lamp_turns
    print *, "Oil on hand: ", oil_gallons
    print *, "Storm watch? ", storm_watch
end program declarations

How it works

1. implicit none turns off the 1950s rule that typed variables by their first letter.
2. integer, real, character(len=12), and logical cover the basics; :: splits type from name.
3. Initializers ride on the declaration, and .true. is how logicals are spelled.

Keywords and builtins used here

• character
• end
• implicit
• integer
• len
• logical
• none
• print
• program
• real

The run, in numbers

Lines

13

Characters to type

396

Tokens

59

Three-star pace

70 tpm

At the three-star pace of 70 tokens a minute, this run takes about 51 seconds.

Type this snippet

Step 2 of 3 in Programs & variables, step 2 of 27 in Language basics.

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Declarations in other languages

• Odin