ArrayFree
ArrayFree
此函数用于释放动态数组占用的缓冲区，并将零维的大小设置为0。
void ArrayFree(
void& array[] // array
);参数
- array[]
[in] 动态数组。
返回值
无返回值。
注意
考虑到所有使用过的内存会一次性被释放，且对数组的主要操作只是访问指示缓冲区，因此可能不太频繁需要使用ArrayFree()函数。缓冲区的大小由终端的执行子系统自动管理。
如果在应用程序的复杂动态环境中需要手动管理内存，ArrayFree()函数允许用户明确且立即释放已由不再需要的动态数组占用的内存。
示例：
#include <Controls\Dialog.mqh>
#include <Controls\Button.mqh>
#include <Controls\Label.mqh>
#include <Controls\ComboBox.mqh>
//--- predefined constants
#define X_START 0
#define Y_START 0
#define X_SIZE 280
#define Y_SIZE 300
//+------------------------------------------------------------------+
//| Dialog class for working with memory |
//+------------------------------------------------------------------+
class CMemoryControl : public CAppDialog
{
private:
//--- array size
int m_arr_size;
//--- arrays
char m_arr_char[];
int m_arr_int[];
float m_arr_float[];
double m_arr_double[];
long m_arr_long[];
//--- labels
CLabel m_lbl_memory_physical;
CLabel m_lbl_memory_total;
CLabel m_lbl_memory_available;
CLabel m_lbl_memory_used;
CLabel m_lbl_array_size;
CLabel m_lbl_array_type;
CLabel m_lbl_error;
CLabel m_lbl_change_type;
CLabel m_lbl_add_size;
//--- buttons
CButton m_button_add;
CButton m_button_free;
//--- combo boxes
CComboBox m_combo_box_step;
CComboBox m_combo_box_type;
//--- current value of the array type from the combo box
int m_combo_box_type_value;
public:
CMemoryControl(void);
~CMemoryControl(void);
//--- class object creation method
virtual bool Create(const long chart,const string name,const int subwin,const int x1,const int y1,const int x2,const int y2);
//--- handler of chart events
virtual bool OnEvent(const int id,const long &lparam,const double &dparam,const string &sparam);
protected:
//--- create labels
bool CreateLabel(CLabel &lbl,const string name,const int x,const int y,const string str,const int font_size,const int clr);
//--- create control elements
bool CreateButton(CButton &button,const string name,const int x,const int y,const string str,const int font_size,const int clr);
bool CreateComboBoxStep(void);
bool CreateComboBoxType(void);
//--- event handlers
void OnClickButtonAdd(void);
void OnClickButtonFree(void);
void OnChangeComboBoxType(void);
//--- methods for working with the current array
void CurrentArrayFree(void);
bool CurrentArrayAdd(void);
};
//+------------------------------------------------------------------+
//| Free memory of the current array |
//+------------------------------------------------------------------+
void CMemoryControl::CurrentArrayFree(void)
{
//--- reset array size
m_arr_size=0;
//--- free the array
if(m_combo_box_type_value==0)
ArrayFree(m_arr_char);
if(m_combo_box_type_value==1)
ArrayFree(m_arr_int);
if(m_combo_box_type_value==2)
ArrayFree(m_arr_float);
if(m_combo_box_type_value==3)
ArrayFree(m_arr_double);
if(m_combo_box_type_value==4)
ArrayFree(m_arr_long);
}
//+------------------------------------------------------------------+
//| Attempt to add memory for the current array |
//+------------------------------------------------------------------+
bool CMemoryControl::CurrentArrayAdd(void)
{
//--- exit if the size of the used memory exceeds the size of the physical memory
if(TerminalInfoInteger(TERMINAL_MEMORY_PHYSICAL)/TerminalInfoInteger(TERMINAL_MEMORY_USED)<2)
return(false);
//--- attempt to allocate memory according to the current type
if(m_combo_box_type_value==0 && ArrayResize(m_arr_char,m_arr_size)==-1)
return(false);
if(m_combo_box_type_value==1 && ArrayResize(m_arr_int,m_arr_size)==-1)
return(false);
if(m_combo_box_type_value==2 && ArrayResize(m_arr_float,m_arr_size)==-1)
return(false);
if(m_combo_box_type_value==3 && ArrayResize(m_arr_double,m_arr_size)==-1)
return(false);
if(m_combo_box_type_value==4 && ArrayResize(m_arr_long,m_arr_size)==-1)
return(false);
//--- memory allocated
return(true);
}
//+------------------------------------------------------------------+
//| Handling events |
//+------------------------------------------------------------------+
EVENT_MAP_BEGIN(CMemoryControl)
ON_EVENT(ON_CLICK,m_button_add,OnClickButtonAdd)
ON_EVENT(ON_CLICK,m_button_free,OnClickButtonFree)
ON_EVENT(ON_CHANGE,m_combo_box_type,OnChangeComboBoxType)
EVENT_MAP_END(CAppDialog)
//+------------------------------------------------------------------+
//| Constructor |
//+------------------------------------------------------------------+
CMemoryControl::CMemoryControl(void)
{
}
//+------------------------------------------------------------------+
//| Destructor |
//+------------------------------------------------------------------+
CMemoryControl::~CMemoryControl(void)
{
}
//+------------------------------------------------------------------+
//| Class object creation method |
//+------------------------------------------------------------------+
bool CMemoryControl::Create(const long chart,const string name,const int subwin,
const int x1,const int y1,const int x2,const int y2)
{
//--- create base class object
if(!CAppDialog::Create(chart,name,subwin,x1,y1,x2,y2))
return(false);
//--- prepare strings for labels
string str_physical="Memory physical = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_PHYSICAL)+" Mb";
string str_total="Memory total = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_TOTAL)+" Mb";
string str_available="Memory available = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_AVAILABLE)+" Mb";
string str_used="Memory used = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_USED)+" Mb";
//--- create labels
if(!CreateLabel(m_lbl_memory_physical,"physical_label",X_START+10,Y_START+5,str_physical,12,clrBlack))
return(false);
if(!CreateLabel(m_lbl_memory_total,"total_label",X_START+10,Y_START+30,str_total,12,clrBlack))
return(false);
if(!CreateLabel(m_lbl_memory_available,"available_label",X_START+10,Y_START+55,str_available,12,clrBlack))
return(false);
if(!CreateLabel(m_lbl_memory_used,"used_label",X_START+10,Y_START+80,str_used,12,clrBlack))
return(false);
if(!CreateLabel(m_lbl_array_type,"type_label",X_START+10,Y_START+105,"Array type = double",12,clrBlack))
return(false);
if(!CreateLabel(m_lbl_array_size,"size_label",X_START+10,Y_START+130,"Array size = 0",12,clrBlack))
return(false);
if(!CreateLabel(m_lbl_error,"error_label",X_START+10,Y_START+155,"",12,clrRed))
return(false);
if(!CreateLabel(m_lbl_change_type,"change_type_label",X_START+10,Y_START+185,"Change type",10,clrBlack))
return(false);
if(!CreateLabel(m_lbl_add_size,"add_size_label",X_START+10,Y_START+210,"Add to array",10,clrBlack))
return(false);
//--- create control elements
if(!CreateButton(m_button_add,"add_button",X_START+15,Y_START+245,"Add",12,clrBlue))
return(false);
if(!CreateButton(m_button_free,"free_button",X_START+75,Y_START+245,"Free",12,clrBlue))
return(false);
if(!CreateComboBoxType())
return(false);
if(!CreateComboBoxStep())
return(false);
//--- initialize the variable
m_arr_size=0;
//--- successful execution
return(true);
}
//+------------------------------------------------------------------+
//| Create the button |
//+------------------------------------------------------------------+
bool CMemoryControl::CreateButton(CButton &button,const string name,const int x,
const int y,const string str,const int font_size,
const int clr)
{
//--- create the button
if(!button.Create(m_chart_id,name,m_subwin,x,y,x+50,y+20))
return(false);
//--- text
if(!button.Text(str))
return(false);
//--- font size
if(!button.FontSize(font_size))
return(false);
//--- label color
if(!button.Color(clr))
return(false);
//--- add the button to the control elements
if(!Add(button))
return(false);
//--- successful execution
return(true);
}
//+------------------------------------------------------------------+
//| Create a combo box for the array size |
//+------------------------------------------------------------------+
bool CMemoryControl::CreateComboBoxStep(void)
{
//--- create the combo box
if(!m_combo_box_step.Create(m_chart_id,"step_combobox",m_subwin,X_START+100,Y_START+185,X_START+200,Y_START+205))
return(false);
//--- add elements to the combo box
if(!m_combo_box_step.ItemAdd("100 000",100000))
return(false);
if(!m_combo_box_step.ItemAdd("1 000 000",1000000))
return(false);
if(!m_combo_box_step.ItemAdd("10 000 000",10000000))
return(false);
if(!m_combo_box_step.ItemAdd("100 000 000",100000000))
return(false);
//--- set the current combo box element
if(!m_combo_box_step.SelectByValue(1000000))
return(false);
//--- add the combo box to control elements
if(!Add(m_combo_box_step))
return(false);
//--- successful execution
return(true);
}
//+------------------------------------------------------------------+
//| Create a combo box for the array type |
//+------------------------------------------------------------------+
bool CMemoryControl::CreateComboBoxType(void)
{
//--- create the combo box
if(!m_combo_box_type.Create(m_chart_id,"type_combobox",m_subwin,X_START+100,Y_START+210,X_START+200,Y_START+230))
return(false);
//--- add elements to the combo box
if(!m_combo_box_type.ItemAdd("char",0))
return(false);
if(!m_combo_box_type.ItemAdd("int",1))
return(false);
if(!m_combo_box_type.ItemAdd("float",2))
return(false);
if(!m_combo_box_type.ItemAdd("double",3))
return(false);
if(!m_combo_box_type.ItemAdd("long",4))
return(false);
//--- set the current combo box element
if(!m_combo_box_type.SelectByValue(3))
return(false);
//--- store the current combo box element
m_combo_box_type_value=3;
//--- add the combo box to control elements
if(!Add(m_combo_box_type))
return(false);
//--- successful execution
return(true);
}
//+------------------------------------------------------------------+
//| Create a label |
//+------------------------------------------------------------------+
bool CMemoryControl::CreateLabel(CLabel &lbl,const string name,const int x,
const int y,const string str,const int font_size,
const int clr)
{
//--- create a label
if(!lbl.Create(m_chart_id,name,m_subwin,x,y,0,0))
return(false);
//--- text
if(!lbl.Text(str))
return(false);
//--- font size
if(!lbl.FontSize(font_size))
return(false);
//--- color
if(!lbl.Color(clr))
return(false);
//--- add the label to control elements
if(!Add(lbl))
return(false);
//--- succeed
return(true);
}
//+------------------------------------------------------------------+
//| Handler of clicking "Add" button event |
//+------------------------------------------------------------------+
void CMemoryControl::OnClickButtonAdd(void)
{
//--- increase the array size
m_arr_size+=(int)m_combo_box_step.Value();
//--- attempt to allocate memory for the current array
if(CurrentArrayAdd())
{
//--- memory allocated, display the current status on the screen
m_lbl_memory_available.Text("Memory available = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_AVAILABLE)+" Mb");
m_lbl_memory_used.Text("Memory used = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_USED)+" Mb");
m_lbl_array_size.Text("Array size = "+IntegerToString(m_arr_size));
m_lbl_error.Text("");
}
else
{
//--- failed to allocate memory, display the error message
m_lbl_error.Text("Array is too large, error!");
//--- return the previous array size
m_arr_size-=(int)m_combo_box_step.Value();
}
}
//+------------------------------------------------------------------+
//| Handler of clicking "Free" button event |
//+------------------------------------------------------------------+
void CMemoryControl::OnClickButtonFree(void)
{
//--- free the memory of the current array
CurrentArrayFree();
//--- display the current status on the screen
m_lbl_memory_available.Text("Memory available = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_AVAILABLE)+" Mb");
m_lbl_memory_used.Text("Memory used = "+(string)TerminalInfoInteger(TERMINAL_MEMORY_USED)+" Mb");
m_lbl_array_size.Text("Array size = 0");
m_lbl_error.Text("");
}
//+------------------------------------------------------------------+
//| Handler of the combo box change event |
//+------------------------------------------------------------------+
void CMemoryControl::OnChangeComboBoxType(void)
{
//--- check if the array's type has changed
if(m_combo_box_type.Value()!=m_combo_box_type_value)
{
//--- free the memory of the current array
OnClickButtonFree();
//--- work with another array type
m_combo_box_type_value=(int)m_combo_box_type.Value();
//--- display the new array type on the screen
if(m_combo_box_type_value==0)
m_lbl_array_type.Text("Array type = char");
if(m_combo_box_type_value==1)
m_lbl_array_type.Text("Array type = int");
if(m_combo_box_type_value==2)
m_lbl_array_type.Text("Array type = float");
if(m_combo_box_type_value==3)
m_lbl_array_type.Text("Array type = double");
if(m_combo_box_type_value==4)
m_lbl_array_type.Text("Array type = long");
}
}
//--- CMemoryControl class object
CMemoryControl ExtDialog;
//+------------------------------------------------------------------+
//| Expert initialization function |
//+------------------------------------------------------------------+
int OnInit()
{
//--- create the dialog
if(!ExtDialog.Create(0,"MemoryControl",0,X_START,Y_START,X_SIZE,Y_SIZE))
return(INIT_FAILED);
//--- launch
ExtDialog.Run();
//---
return(INIT_SUCCEEDED);
}
//+------------------------------------------------------------------+
//| Expert deinitialization function |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
{
//---
ExtDialog.Destroy(reason);
}
//+------------------------------------------------------------------+
//| Expert chart event function |
//+------------------------------------------------------------------+
void OnChartEvent(const int id,
const long &lparam,
const double &dparam,
const string &sparam)
{
ExtDialog.ChartEvent(id,lparam,dparam,sparam);
}最后更新于