Thread: About function pointers...

The name of your function pointer would be right of the asterisk. Function pointers are most useful in situations where you must call an unknown function defined by the user (of your code). A common example is in Windows programming. In order for your program to process messages sent by the operating system, you can give it the name of a callback function you have defined. You wouldn't have any reason to use function pointers in most applications and when programming in C++ (and you're developing for a framework that allows it) you can use functors instead.

Code:

double add(double x, double y) {return x+y;}  // two functions to point to
double subtract(double x, double y) {return x-y;}

// ...

double (*funcpointer)(double, double);  // declare the function pointer
    // it's a pointer to a function that returns a double and takes two doubles as arguments

// ...

if(input == "+") funcpointer = add;  // set the function pointer (method #1)
else funcpointer = &subtract;  // method #2

// ...

funcpointer(num1, num2);  // call the function (method #1)
(*funcpointer)(num1, num2);  // method #2

Having a bad day 7stud?

That calls the function that the function pointer points to, which you´ll have to do eventually for it to be useful.

Unless you mean the return value. Okay, then, do this:

Code:

double one = funcpointer(num1, num2);  // call the function (method #1)
double two = (*funcpointer)(num1, num2);  // method #2