c++ - How to make types for indexing -

i have like:

array definition:

array<array<value, n_foo_per_bar>, n_bar> arr; 

access function:

value getfoo(int baridx, int fooidx){   return arr[baridx][fooidx]; } 

for-loop:

for(int = 0; < n_bar; ++){   for(int j = 0; j < n_foo_per_bar; j ++){     arr[i][j].dosomething();   } }  

problem: indices foo , bar can mixed when using getfoo(...).

i define type baridx , fooidx , compiler should complain when mix them up.

the access function like:

function getfoo(badidx baridx, fooidx fooidx){   return arr[baridx][fooidx]; } 

the for-loop like:

for(baridx = 0; < n_bar; ++){   for(fooidx j = 0; j < n_foo_per_bar; j ++){     arr[i][j].dosomething();   } }  

so i'm looking how define type (a) issue warning/error when used @ wrong place (b) still behaves as integer possible, for loop , array access []. should work on cuda, prefer use simple language constructs rather perfect solution.

the difficulty doing can't inherit int in c++, need provide wrapper not implicitly converts , int, provides necessary operators can things like:

baridx = 0; ++a; 

you might want start simple this:

template <typename t> class integralwrapper {     t value; public:     typedef t value_type;     integralwrapper() :value() {}     integralwrapper(t v) :value(v) {}     operator t() const { return value; } }; 

then add operators need later. define index classes this:

class baridx : public integralwrapper<int> {}; class fooidx : public integralwrapper<int> {}; 

alternatively, here seemingly pretty complete integral wrapper solution taken this question use.