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TextSetFont
The function sets the font for displaying the text using drawing methods and returns the result of that operation. Arial font with the size -120 (12 pt) is used by default.
كود PHP:TextSetFont
bool TextSetFont(
const string name, // font name or path to font file on the disk
int size, // font size
uint flags=0, // combination of flags
int orientation=0 // text slope angle
);
strict compilation ,default compilation
http://www7.0zz0.com/2017/10/01/08/285099077.png
extern او input
Unlike input variables, values of extern variables can be modified in the program during its operation
A variable with the input modifier can't be changed inside mql4-programs
http://www2.0zz0.com/2017/10/02/23/174772277.png
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Use of several functions of the same name from different execution contexts in a program may cause ambiguity. To avoid the ambiguity of function calls, always explicitly specify the function scope using the scope resolution operation.
http://www4.0zz0.com/2017/10/03/01/924554823.png
مااهو الفرق بين الكودين اسفل
كود PHP://+------------------------------------------------------------------+
class CObjectA
{
public:
CObjectA(){Print(__FUNCTION__," ConstructorA");Sleep(2000);}
~CObjectA(){Print(__FUNCTION__," DestructorA");Sleep(2000);}
};
//+------------------------------------------------------------------+
class CObjectB
{
public:
CObjectB(){Print(__FUNCTION__," ConstructorB");Sleep(2000);}
~CObjectB(){Print(__FUNCTION__," DestructorB");Sleep(2000);}
};
//--- declaring the objects globally
CObjectB second;
CObjectA first;
//+------------------------------------------------------------------+
void OnStart()
{
Print(__FUNCTION__);
}
كود PHP://+------------------------------------------------------------------+
class CObjectA
{
public:
CObjectA(){Print(__FUNCTION__," ConstructorA");Sleep(2000);}
~CObjectA(){Print(__FUNCTION__," DestructorA");Sleep(2000);}
};
//+------------------------------------------------------------------+
class CObjectB
{
public:
CObjectB(){Print(__FUNCTION__," ConstructorB");Sleep(2000);}
~CObjectB(){Print(__FUNCTION__," DestructorB");Sleep(2000);}
};
//--- declaring the objects globally
CObjectA first;
CObjectB second;
//+------------------------------------------------------------------+
void OnStart()
{
Print(__FUNCTION__);
}
ج: order of initialization match the order of declaration of variables in GlobalVar script, and deinitialization is done in reverse order before MQL4-program roll-out.
http://www13.0zz0.com/2017/10/03/09/726975291.pngاقتباس:
ج: order of initialization match the order of declaration of variables in GlobalVar script, and deinitialization is done in reverse order before MQL4-program roll-out.
https://www.mql5.com/en/articles/28
Local variables are initialized only if they are used in program. If a variable is declared, but the block of code in which it is declared is not executed, then this variable is not created and hence it is not initialized.
مهم جددا لسرعة تنفيذ الاوامر
كود:f instead of using a variable for the array size you call the ArraySize() function when checking condition in a for loop, the looping time may be significantly prolonged as the ArraySize() function will be called at every loop iteration. So the function call takes more time than calling a variable:
for(int i=0; i<ArraySize(Variable); i++){
// some manipulations on the Variable[i] element
}
Use of the above code is not recommended.
If the program algorithm allows for backward loop iteration, you can do without a variable for the array size:
for(int i=ArraySize(Variable)-1; i>=0; i--){
// some manipulations on the Variable[i] element
}
In this case, the ArraySize() function will be called only once at the beginning of the loop, and the loop will run fast.
Preprocessors are a way of making text processing with your C program before they are actually compiled. Before the actual compilation of every C program it is passed through a Preprocessor. The Preprocessor looks through the program trying to find out specific instructions called Preprocessor directives that it can understand. All Preprocessor directives begin with the # (hash) symbol. C++ compilers use the same C preprocessor.[1]
The preprocessor is a part of the compiler which performs preliminary operations (conditionally compiling code, including files etc...) to your code before the compiler sees it. These transformations are lexical, meaning that the output of the preprocessor is still text.
http://fresh2refresh.com/c-programmi...or-directives/
The binary tree is a useful data structure for rapidly storing sorted data and rapidly retrieving stored data
It begins with a root node, which contains the original key value. The root node has two child nodes; each child node might have its own child nodes. Ideally, the tree would be structured so that it is a perfectly balanced tree, with each node having the same number of child nodes to its left and to its right. A perfectly balanced tree allows for the fastest average insertion of data or retrieval of data. The worst case scenario is a tree in which each node only has one child node, so it becomes as if it were a linked list in terms of speed