Hello Fortran

A Fortran program sits between program name and end program name. Modern code is free-form source in .f90 files: no fixed columns.

print *, 'hello' writes a line using list-directed format, where * means 'let the compiler choose the layout'. Strings use single or double quotes.

Comments start with ! and run to the end of the line. Fortran is case-insensitive: PRINT and print are the same.

Compile and run with gfortran hello.f90 -o hello && ./hello. Add -Wall -std=f2018 to catch mistakes early.

Long statements continue onto the next line with a trailing &.

! hello.f90
program hello
  implicit none
  print *, 'hello'
  print *, 'two plus three is', &
           2 + 3
end program hello