/*/ * Iterators in Rust are awesome and very * powerful. In this code I wanted to recreate * a few iterator functions of Rust (next, * for_each, rev, and find) in C++. It turns * out that Rust is the superior language (not * only for implementing iterators), yet it * is possible to create something similar * in C++. * /*/ #include #include using namespace std; template class Iterator{ private: T* pos; T* end; Iterator(T* _start, T* _end): pos(_start), end(_end) {} public: T next() { if (pos < end) pos++; else if (pos > end) pos--; else return -1; return *pos; } Iterator* clone() { return new Iterator(pos, end); } Iterator(vector *vec): pos(&vec->at(0) - 1), end(&vec->at(vec->size() - 1)) {} void for_each(auto lambda) { while(this->next() != -1) lambda(pos); } Iterator* rev() { int offset = (pos > end) ? 1 : -1; T* swap = end; end = pos - offset; pos = swap - offset; return this; } int find(auto lambda) { while(this->next() != -1) if(lambda(pos)) return (pos > end) ? (pos - end) : (end - pos); return -1; } }; int main() { auto* vec = new vector{0, 1, 2, 3, 4}; auto* iter = new Iterator(vec); auto* iter2 = iter->clone(); iter ->rev() // reverse the iterator ->for_each([](auto x) { *x = *x + 10; cout << *x << endl; }); // find index of the first element with value 12 int pos = iter2 ->find([](auto x) { return *x == 12; }); if (pos != -1) cout << endl << vec->at(pos) << endl; }

Rust-like iterators in C++