Constuctor chaining, better/more efficient moving

vector/vec.cc

@@ -2,14 +2,16 @@
 #include <cstddef>
 #include <cstring>
 #include <iostream>
+#include <iterator>
 
-Vec::Vec() : cap(INITIAL_LEN), w_idx(0), arr(nullptr) {
+Vec::Vec() : Vec(INITIAL_LEN) {}
-    std::cout << "Allocating vector" << std::endl;
+
-    arr = new T[INITIAL_LEN];
+Vec::Vec(std::size_t size) : cap(size), w_idx(0), arr(new T[size]) {
+    std::cout << "Allocating vector of size " << size << std::endl;
 }
 
-Vec::Vec(std::initializer_list<T> il) : Vec() {
+Vec::Vec(std::initializer_list<T> il) : Vec(il.size()) {
-    for (auto &a : il) push_back(a);
+    for (auto &elem : il) push_back(std::move(elem));
 }
 
 Vec::~Vec() {
@@ -26,12 +28,18 @@ T &Vec::operator[](std::size_t idx) const noexcept {
     exit(1);
 }
 
-void Vec::push_back(const T &value) noexcept {
+void Vec::push_back(const T &value) {
     arr[w_idx++] = value;
 
-    if (w_idx == cap) {
+    if (w_idx == cap)
         resize(cap * 2);
 }
+
+void Vec::push_back(T &&value) {
+    arr[w_idx++] = std::move(value);
+
+    if (w_idx == cap)
+        resize(cap * 2);
 }
 
 std::size_t Vec::size() const { return w_idx; }
@@ -39,9 +47,10 @@ std::size_t Vec::size() const { return w_idx; }
 std::size_t Vec::capacity() const noexcept { return cap; }
 
 void Vec::resize(std::size_t newsize) {
-    std::cout << "Reallocating" << std::endl;
+    std::cout << "Reallocating: " << cap << " to " << newsize << std::endl;
+
     T *newarr = new T[newsize];
-    std::memcpy(newarr, arr, w_idx);
+    std::move(arr, arr + w_idx, newarr);
     delete[] arr;
     arr = newarr;
     cap = newsize;

vector/vec.h

@@ -13,6 +13,7 @@ class Vec {
 
   public:
     Vec();
+    explicit Vec(std::size_t);
     Vec(std::initializer_list<T>);
     Vec(const Vec &other);                // Copy
     Vec(Vec &&other) noexcept;            // Move
@@ -25,7 +26,8 @@ class Vec {
     std::size_t size() const;
     std::size_t capacity() const noexcept;
 
-    void push_back(const T &value) noexcept;
+    void push_back(const T &value); // May except
+    void push_back(T &&value);
     void pop_back() noexcept;
     void clear() noexcept;