Check row and column indices. Fortran conventionally numbers from one (1), whereas C and C++ number from zero (0). This difference in numbering conventions can lead to unexpected results with regard to row and column indices when your application modifies a problem or exercises query routines.

It is important that you use the Fortran declaration IMPLICIT NONE to help you detect any unintended type conversions, because such inadvertent conversions frequently lead to strange application behavior.