# StringToDouble

The function converts string containing a symbol representation of number into number of double type.

```
double  StringToDouble(
   string  value      // string
   );

```

Parameters

value

[in]  String containing a symbol representation of a number.

Return Value

Value of double type.

Example:

```
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//--- string to convert
   string str = "12345.54321";
//--- convert the input string as a real number into a double type variable
   double converted=StringToDouble(str);
//--- display the resulting number accurate to 8 decimal places in the journal
   PrintFormat("The string '%s' is converted to the real number %.8f", str, converted);
   /*
   result:
   The string '12345.54321' is converted to the real number 12345.54321000
   */
  }

```

See also

[NormalizeDouble](/en/docs/convert/normalizedouble), [Real types (double, float)](/en/docs/basis/types/double), [Typecasting](/en/docs/basis/types/casting)