Object create operator new

Overview

The new operator creates an object of the appropriate size, invokes its constructor, and returns a descriptor for the created object. If the creation fails, it returns a null descriptor, which can be compared with the NULL constant.

Usage Constraints

Applicable only to class objects.

Cannot be applied to structures.

Should not be used for creating arrays of objects; use ArrayResize() for arrays.

Return Value

A descriptor of the created object.

NULL constant if creation fails.

Object Lifetime

Objects created with the new operator must be explicitly removed using the delete operator.

Related Concepts

[Object descriptor is not a memory address pointer.](https://docs.mql4.com/en/basis/operators/newoperator#note)

[Initialization of Variables](/basis/variables/initialization)

[Visibility Scope and Lifetime of Variables](/basis/variables/variable_scope)

[Creating and Deleting Objects](/basis/variables/object_live)

[Object Delete Operator delete](/basis/operators/deleteoperator)

Example

void CTetrisField::NewShape()
  {
   m_ypos=HORZ_BORDER;
//--- randomly create one of the 7 possible shapes
   int nshape=rand()%7;
   switch(nshape)
     {
      case 0: m_shape=new CTetrisShape1; break;
      case 1: m_shape=new CTetrisShape2; break;
      case 2: m_shape=new CTetrisShape3; break;
      case 3: m_shape=new CTetrisShape4; break;
      case 4: m_shape=new CTetrisShape5; break;
      case 5: m_shape=new CTetrisShape6; break;
      case 6: m_shape=new CTetrisShape7; break;
     }
//--- draw
   if(m_shape!=NULL)
     {
      //--- pre-settings
      m_shape.SetRightBorder(WIDTH_IN_PIXELS+VERT_BORDER);
      m_shape.SetYPos(m_ypos);
      m_shape.SetXPos(VERT_BORDER+SHAPE_SIZE*8);
      //--- draw
      m_shape.Draw();
     }
//--- 
  }