operator double

Applies To

OField

OParameter

OValue

Description

This method returns the object's value as a double.

Usage

operator double() const

Remarks

This method hands the value of the object back to the caller as a double. If the object's current value is not a double, the method attempts to convert the value. This can fail., resulting in a return of the value 0.0.

Return Value

The value of the field as a double; 0.0 on failure.

Example

Sum all the salaries of employees:

// open the employee database
ODatabase odb("ExampleDB", "scott", "tiger");

// open a dynaset on the employee's table
ODynaset odyn(odb, "select sal, comm from employees");

// get a field on the salary for speed
OField salf = odyn.GetField("sal");
/*

By using the = operator in the declaration of salf we are invoking the copy
constructor. It is copying the temporary object that is returned by the GetField
method.
*/

// sum the salaries
double sumsal = 0.0;
odyn.MoveFirst();
while (!odyn.IsEOF())
{
    sumsal += (double) salf;
    odyn.MoveNext();
}

// of course, we could have done the same thing (faster) with:
ODatabase odb("ExampleDB", "scott", "tiger");
ODynaset odyn(odb, "select sum(sal) from employees");
odyn.GetFieldValue(0, &sumsal);
// the server is good at that kind of bulk calculation