An if (cond) then ... else ... end if block picks one branch. Comparisons return a logical value.

Program

Play the program to choose pass for a high score.

if_then_else.f90
program if_then_else
    implicit none
    integer :: score
    character(len=8) :: grade
    score = 82
    if (score >= 80) then
        grade = "pass"
    else
        grade = "retry"
    end if
    print '(A)', trim(grade)
end program if_then_else
if block `if ... then ... else ... end if` chooses a branch.
logical `score >= 80` evaluates to `.true.` or `.false.`.
trim `trim` drops trailing blanks before printing.