Ideas in this flowchart

• C function pointers allow functions to be referenced and called through pointer variables.
• A function pointer’s type specifies the return type and parameter types of the referenced function.
• int (*ptrToFunc)(int, double, char) = NULL;
• The pointer can reference any function that takes an int, double, and char and returns an int.
• A pointer to a function taking one double argument can be declared as double (*ptr)(double) = NULL;
• Assigning ptr = sqrt allows x = ptr(2.0), producing approximately 1.4142.
• Assigning ptr = fabs allows x = ptr(-10.5), producing 10.5.
• Function pointers are generally used to pass and return functions as arguments to other functions, such as callbacks.
• The callback use of function pointers is discussed further in Chapter 25.
• A function pointer can also be used in an expression such as double x = ptrToSqrt(2.0);