Skip to main content

Array of Functions

In the article Pointers to Function, we saw how pointers can be made to point at functions and hence can be used to invoke them.

By far the most important use of pointers to functions is to have arrays of functions. This can be achieved as stated below

You already know that we can have arrays of pointers and pointers can be made to point at functions. So combining both we can have array of pointers to functions put differently, we can have array of functions.

The example program below demonstrates how we can have array of functions; please note that this concept is mostly used in writing compilers and interpreters, so you shouldn’t expect the program to do anything serious or useful!

  // Program to demonstrate
  // array of functions
  #include<iostream.h>

  // -- FUNCTION PROTOTYPES --
  void func1();
  void func2();
  void func3();
  void func4();
  void func5();
  // -- ENDS --

  void main()
  {
   // notice the prototype
   void (*ptr[5])();

   // arrays are made to point
   // at the respective functions
   ptr[0]=func1;
   ptr[1]=func2;
   ptr[2]=func3;
   ptr[3]=func4;
   ptr[4]=func5;

   // now the array elements
   // point to different functions
   // which are called just like
   // we access the elements of
   // an array
   for(int i=0;i<5;i++)
     (*ptr[i])();
  }

  // -- FUNCTIONS DEFINITION --
  void func1()
  {
   cout<<"Called Func1!\n";
  }

  void func2()
  {
   cout<<"Called Func2!\n";
  }

  void func3()
  {
   cout<<"Called Func3!\n";
  }

  void func4()
  {
   cout<<"Called Func4!\n";
  }

  void func5()
  {
   cout<<"Called Func5!\n";
  }
  // -- ENDS --

Good-Bye!

Related Articles:

Popular posts from this blog

Fix For Toshiba Satellite "RTC Battery is Low" Error (with Pictures)

RTC Battery is Low Error on a Toshiba Satellite laptop "RTC Battery is Low..." An error message flashing while you try to boot your laptop is enough to panic many people. But worry not! "RTC Battery" stands for Real-Time Clock battery which almost all laptops and PCs have on their motherboard to power the clock and sometimes to also keep the CMOS settings from getting erased while the system is switched off.  It is not uncommon for these batteries to last for years before requiring a replacement as the clock consumes very less power. And contrary to what some people tell you - they are not rechargeable or getting charged while your computer or laptop is running. In this article, we'll learn everything about RTC batteries and how to fix the error on your Toshiba Satellite laptop. What is an RTC Battery? RTC or CMOS batteries are small coin-shaped lithium batteries with a 3-volts output. Most laptops use

The Best Way(s) to Comment out PHP/HTML Code

PHP supports various styles of comments. Please check the following example: <?php // Single line comment code (); # Single line Comment code2 (); /* Multi Line comment code(); The code inside doesn't run */ // /* This doesn NOT start a multi-line comment block /* Multi line comment block The following line still ends the multi-line comment block //*/ The " # " comment style, though, is rarely used. Do note, in the example, that anything (even a multi-block comment /* ) after a " // " or " # " is a comment, and /* */ around any single-line comment overrides it. This information will come in handy when we learn about some neat tricks next. Comment out PHP Code Blocks Check the following code <?php //* Toggle line if ( 1 ) {      // } else {      // } //*/ //* Toggle line if ( 2 ) {      // } else {      // } //*/ Now see how easy it is to toggle a part of PHP code by just removing or adding a single " / " from th

Designing a Simple Order Form Application in PHP

Ok guys, for this post we’re going to create a simple yet complete order form page. Order forms are used on many sites to take customers order online. Order forms should have the capability to take orders from visitors regarding what items they want to purchase and store the information for further processing. For this post’s example, we are going to create an order form for a Book Seller. The form will be designed to take order of five different items (books). Our order form application should be able to take order of five different items in any separate quantities tht user wants, it should also ask for shipping address and name of the customer. It should then store the information provided in a file along with the date and time order was placed. The application should also be able to take any number of orders and store them all linearly for further human processing. For this, we need a front end of a HTML form to which the user would interact a