MQL4 Reference / Language Basics / Data Types / Integer Types / Bool Type

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Bool Type

The bool type is intended to store the logical values of true or false, numeric representation of them is 1 or 0, respectively.

Examples:

bool a = true;
bool b = false;
bool c = 1;

The internal representation is a whole number 1 byte large. It should be noted that in logical expressions you can use other integer or real types or expressions of these types - the compiler will not generate any error. In this case, the zero value will be interpreted as false, and all other values - as true.

Examples:

   int i=5;
  double d=-2.5;
  if(i) Print("i = ",i," and is set to true");
  else Print("i = ",i," and is set to false");
 
  if(d) Print("d = ",d," and has the true value");
  else Print("d = ",d," and has the false value");
 
  i=0;
  if(i) Print("i = ",i," and has the true value");
  else Print("i = ",i," and has the false value");
 
  d=0.0;
  if(d) Print("d = ",d," and has the true value");
  else Print("d = ",d," and has the false value");
 
//--- Execution results
//   i= 5 and has the true value
//   d= -2.5 and has the true value
//   i= 0 and has the false value
//   d= 0 and has the false value

See also

Boolean Operations, Precedence Rules