c++ - Increase capacity for vector -

disclaimer 1 - i'm new programming disclaimer 2 - have searched , searched, can't find i'm looking for.

for project, more or less re-writing vector class in more stripped down form. part i'm hung writing push_back method. all's until have increase capacity of array.

i assume should done create new vector increased size, , copy elements old vector new one, use assignment operator assign oldvector newvector.

i have either written push_back method incorrectly, overloaded = operator incorrectly, or else i'm lacking in understanding on should happening. appreciated.

when compiling, error "lvalue required left operand of assignment" on line assign = tempv

template <class t> vector<t>& vector<t>::operator = (const vector<t> & v) {     int newsize = v.size();     int newcapacity = v.getcapacity();     data = new t[newcapacity];     for(int = 0; < newsize; i++)         data[i] = v.data[i];     return *this; }  template <class t> void vector <t> :: push_back(const t & number) {     if(numitems == capacity)     {         vector <t> tempv(this->capacity * 2);         for(int = 0; < numitems; i++)             tempv.data[i] = data[i];         *this = tempv;     }     if(numitems < capacity)         data[numitems++] = number; } 

update see why code wouldn't compile while using

*this = tempv; 

in copy method, using v.size , not v.size() method. after fixing that, code compiles , runs, capacity of vector same , did not increase expecting. i'm still missing something. code above has been updated.

thanks again any/all help!

why have create new vector<t>? create new array:

template <class t> void vector <t> :: push_back(const t & number) {     if(numitems == capacity)     {         capacity *= 2;         t* newdata = new t[capacity];         std::copy(data, data + numitems, newdata);         delete[] data;         data = newdata;     }      data[numitems++] = number; }