List of Simple Predefined Names of Variables
Ask - last known sell-price of a current security;
Bid - last known buy-price of a current security;
Bars - number of bars on a current chart;
Point - point size of a current security in quote currency;
Digits - number of digits after a decimal point in the price of a current security.
List of Predefined Names of Arrays-Timeseries
Time - opening time of each bar on the current chart;
Open - opening price of each bar on the current chart;
Close - closing price of each bar on the current chart;
High - maximal price of each bar on the current chart;
Low - minimal price of each bar on the current chart;
Volume - tick volume of each bar on the current chart.
Local and Global Variables
Local variable is a variable declared within a function. The scope of local variables is the body of the function, in which the variable is declared. Local variable can be initialized by a constant or an expression corresponding to its type.
Global variable s a variable declared beyond all functions. The scope of global variables is the entire program. A global variable can be initialized only by a constant corresponding to its type (and not expression). Global variables are initialized only once before stating the execution of special functions.
External variable is a variable, the value of which is available from a program properties window. An external variable is declared outside all functions and is a global one - its scope is the whole program. When declaring an external variable, modifier 'extern' should be indicated before its value type:
extern int Number;// External variable of integer type