Answer 1

If you have a normal c array, int arr[2] or similar:

int arr[2] = {3,1};
int elm=3; //What you need to find.
int pos = std::distance(arr,std::find(arr,arr+2,elm));
if(pos<2) std::cout<<pos;
else std::cout<<-1;

You will need to include <iterator> for std::distance