Enable all warnings and fix a few

SConstruct

@@ -4,5 +4,7 @@
 env = DefaultEnvironment(tools=['default', 'compilation_db'])
 env.CompilationDatabase()
 
+env.Append(CCFLAGS=["-Wall", "-Wextra", "-Werror", "-pedantic"])
+
 # Build the output program
 Program('vector.out', Glob('*.cpp'))

Vector.h

@@ -25,7 +25,7 @@ class Vector {
     }
 
     // Move Constructor using the copy-and-swap-idiom
-    Vector(Vector &&other) : data((T *)::operator new(capacity * sizeof(T))) {
+    Vector(Vector &&other) : data(nullptr) {
         swap(*this, other);
     }
 
@@ -160,9 +160,9 @@ class Vector {
     }
 
   private:
-    T *data;
-    unsigned int element_count;
     unsigned int capacity;
+    unsigned int element_count;
+    T *data;
 
     bool is_using_excessive_memory() {
         return 10 + element_count * 2 < capacity;