Static variables

Declaration

Declared using the static keyword before the data type.

Example: static int flag = 10;

Initialization

Can be initialized by a constant or constant expression corresponding to its type.

If initial values are not specified, they take zero initial values.

Initialized only once after the program is loaded.

Lifetime and Scope

**Local Static Variables:** Retain their values throughout the function lifetime. Contain values from the previous call on subsequent calls.

**Scope:** Local to the block in which the variable is defined.

**Lifetime:** The lifetime of the MQL4 program (same as global variables).

Usage

Any variables in a block, except formal parameters, can be defined as static.

Unlike non-static local variables, which are allocated on the program stack, static variables have a program-wide lifetime.

Example

int Counter()
{
  static int count;
  count++;
  if(count % 100 == 0) Print("Function Counter has been called ", count, " times");
  return count;
}void OnStart()
{
  int c = 345;
  for(int i = 0; i < 1000; i++)
  {
    int c = Counter();
  }
  Print("c = ", c);
}

Related Concepts

Data Types

Initialization of Variables

Visibility Scope and Lifetime of Variables

Static Class Members