header files - What difference does it make when I include <limits> or <limits.h> in my c++ code -

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can please explain this?

    #include <iostream>     #include <limits.h>

or

    #include <iostream>     #include <limits>

<limits> c++ standard library header providing similar insights c header <limits.h> (which available in c++ <climits>), written in way that's more useful , safe in c++ programs:

  • say have template <typename numeric> ..., , code inside wants know minimum , maximum value of numeric type parameter user instantiated template with: can use std::numeric_limits<numeric>::min() , ...::max(); if wanted access same values <climits>, it'd hard know of schar_min, shrt_min, int_min, long_min etc. use , you'd have switch between them - lots of code trivial

  • <climits> has lots of macros, , macros don't respect namespaces or scopes way "normal" c++ identifiers - substitutions made pretty indescriminately - make program more error prone

  • <limits> gives more insight numeric types, such whether they're signed, number of base-10 digits can handle, whether can represent infinity or not-a-number sentinel values etc. (see header docs fuller list , information)


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