We know that a pointer to a float data object is declared as follows:
float* p;

Thus the formal definition of the swap function must be:

void swap ( float* p, float* q ) {
float tt;
tt = *p;// p is a pointer, *p is the value
*p = *q;
*q = tt;
}
To access the data object referenced by a pointer, use the dereferencing operation *,as in

*p = *p + 1;adds 1 to the contents of p, as does
p[0] = p[0] + 1;
while
p[0] = p[1];is the same as
*p = *(p + 1);
p is incremented by the size of the object.

But what about
*p = *(p++);

*It is important to remember that a pointer is an address of an object of a certain type. You must keep track of the type_sizewhen you are manipulating addresses of objects, and when manipulating the objects themselves.

January 21, 1999

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JH/TM