逻辑类型的无法分类的语句错误-Fortran

Question

program test
logical :: check
check = 2 < 3 < 5
print *, check
end program test

When trying to compile, it will give this error:

Error(s): source_file.f:5:0:

check = 2 < 3 < 5 1 Error: Unclassifiable statement at (1)

where is the problem?

you can test it online here: https://rextester.com/l/fortran_online_compiler

Answer 1

如果要检查2小于3，3小于5，则确实需要两次比较和一个布尔运算符

check = (2 < 3) .and. (3 < 5)