Implement the following generic Standard Library function defined in <algo>:
template <class Src>
bool equal (Src I, Src j, Src p);
// Returns true iff the subsequence i…(j-1) is the same
// as the subsquence p…(p+1)where n = i - j.
// Invariant: no elements are changed.
//---------------------------
template <class Src>
bool equal (Src I, Src j, Src p);
// Returns true iff the subsequence i…(j-1) is the same
// as the subsquence p…(p+1)where n = i - j.
// Invariant: no elements are changed.
//---------------------------