vector简单实现

#include<iostream>"https://github.com/fookwood/fkcode/network"template<class Object>class Vector{private:int theSize; //元素的个数int theCapacity; //容量Object *objects; //指向new分配的资源public:explicit Vector( int initSize = 0 ):theSize( initSize ),theCapacity( initSize + SPACE_CAPACITY ){objects = new Object[ theCapacity ];}//用explicit避免隐式类型转换Vector( const Vector & rhs ):objects( NULL ){operator=( rhs );}//copy constructor~Vector(){delete [] objects;}const Vector & operator= ( const Vector & rhs ){if( this != &rhs ){//如果是本身的话就不用再操作了delete [] objects;theSize = rhs.size();theCapacity = rhs.capacity();objects = new Object[ capacity() ];for( int k = 0; k < theSize; k++ )//拷贝元素  objects[k] = rhs.objects[k];  }  return *this;  }// above,the "big three"  void resize( int newSize ){  if( newSize > theCapacity )reserve( newSize*2 + 1 ); //theSize = newSize;}//每次空间不够的时候,就重新获得2倍于当前容量的空间,+1是为了防止0的情况void reserve( int newCapacity ){if( newCapacity < theSize ) return;Object *oldArray = objects;objects = new Object[ newCapacity ];for( int k = 0; k < theSize; k++ )objects[k] = oldArray[k];theCapacity = newCapacity;delete [] oldArray;}//获取新的空间,拷贝,释放旧的//[]操作符,non-const和const版的..Object & operator[] ( int index ) { return objects[ index ]; }const Object & operator[] ( int index ) const { return objects[ index ]; }bool empty() const { return size() == 0; }int size() const { return theSize; }int capacity() const { return theCapacity; }void push_back( const Object & x ){if( theSize == theCapacity )reserve( 2*theCapacity + 1 );objects[ theSize++ ] = x;}//插入元素void pop_back() { theSize--; }const Object & back() const { return objects[ theSize-1 ]; }typedef Object * iterator;//用原生指针替代迭代器typedef const Object * const_iterator;iterator begin() { return &objects[0]; }const_iterator begin() const { return &objects[0]; }iterator end() { return &objects[ theSize ]; }const_iterator end()   const { return &objects[ theSize ]; }enum{ SPACE_CAPACITY = 4 };//初始容量};int main() {//进行简单的测试Vector V;for( int i = 0; i < 100; i++ )V.push_back( i );for( Vector::iterator it = V.begin(); it != V.end(); it++ )std::cout << *it << std::endl;const Vector v( V );for( Vector::const_iterator it = V.begin();it != V.end(); it++ )std::cout << *it << std::endl;return 0;}

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