question about fortran continue statement in a for loop

Question

I am analyzing a code in fortran and have a simple question.

I want to know what the "continue" statement at 100 and 200 in the code below does.

Does it increment the i and j counters? If so, wouldn't if( .not. flg ) then condition contain the flg value that is the "last value" of flg in the loop j = i+1 to N?

    do 100 i = 1, N-1
            flg = .false.
            do 200 j = i+1, N
                if( "my condition" ) flg = .true.
200         continue

            if( .not. flg ) then
                ! do something here. 
            endif
100 continue

score 5 · Answer 1 · answered Feb 01 '10 at 11:00

Th CONTINUE statement simply marks the end of the loop indicated by its numeric statement number - it doesn't increment anything. It certainly has no effect on flg in your code. There's a simple explanation of its use here.

score 4 · Accepted Answer · answered Feb 01 '10 at 10:57

4

AFAIK, CONTINUE in fortran does nothing.

It's used only for convenience in DO loop semantics. This is not like C.

answered Feb 01 '10 at 10:57

Pavel Radzivilovsky

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score 2 · Answer 3 · answered Feb 01 '10 at 20:08

2

This is old Fortran, which used typically used labeled continue statements to mark do loops. Fortran 90 and later provides an "end do" statements.

answered Feb 01 '10 at 20:08

M. S. B.

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score 0 · Answer 4 · answered Nov 17 '13 at 16:49

I am answering after more than three years since the question was asked in Feb'2010 because I saw the question now only and find that the answers would have been more detailed and complete. Indeed the logical variable flg shall have "last value" of flg in the loop j = i+1 to N because the inner do loop designated by label 200 shall run from j = i+1 to N for each value of i (= 1, N-1,1). The condition "my condition" must plays important role in not making this inner loop trivial otherwise.

question about fortran continue statement in a for loop

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