program test real(8) :: x1, x2(5) real(8), allocatable :: x3(:) allocate(x3(5)) print *, x1 print *, x2 print *, x3 end program Using GFortran 12.1.1, I get random values for x1 and x2 at each run, but x3 remains filled with zeros. How come?

The variables x1, x2, x3 are being printed out despite their status of ‘undefined’. The behavior of the program is ‘undefined’. Different compilers may print different results. It is wrong to ask the question “how come?” in such a situation, as far as the Fortran language rules are concerned. The …

Undefined variables

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Sideboard June 10, 2022, 9:18am 9

I didn’t expect that. What is the “arithmetic operation” here? Implicitly converting snan into strings to print them? Thought that would be valid for any value.

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Undefined variables

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