Why “i” is used in for loops

Which in turn is certainly derived from index variables in math (i for summation/product; i,j for matrix indexing and so on).

Old FORTRAN programmer here... I hated implicit data types and was never happier when IMPLICIT NONE was introduced.

c.f. "God is real (unless declared integer)" https://ell.stackexchange.com/questions/163171/god-is-real-u...