Programming and Graphics

5.1 Pointers to scalars and characters 133

{

double a=8.45;

double * memada;

double ** memadb;

memada = &a;

memadb = &memada;

double verifya = *memada;

double verifyb = **memadb;

cout << a << endl;

cout << memada <<""<<memadb << endl;

cout << verifya <<""<<verifyb << endl;

return 0;

}

Running the code prints on the screen:

8.45

0xbfd40150 0xbfd4014c

8.45 8.45

Third- and high-order pointers are defined in similar ways.

Inverse typecasting

At the beginning of this section, we saw that the memory address of
a variable can be stored as a regular integer of a non-pointer type through
typecasting.

Double use of the dereference operator allows us to map the integer back
into the variable. To demonstrate the method, we consider the statements:

float b=1.2;

unsigned int mab = (unsigned int) &b;

cout << b << " " << mab <<""<<*(float*) mab << endl;

The output on the screen is:

1.2 3215432204 1.2

The expression (float) mabtypecasts the integermabas a pointer corre-
sponding to a float, and then extracts the pointer content.