Difference between Top-Down and Bottom- Up Programming

Top Down Programming

Top down approach is used by procedure oriented language like C. In this concern A problem is solved by the top level wise i.e. A main function is created which draw a sketch that how will our program be started and then find out the low level modules further. The problem is divided into the sub modules and implemented each coding separately, which called and control by the main function. Top down approach is no longer popular today.

Bottom Up Programming

Bottom up approach is used by the object oriented language like C++, Java, C#, VB.Net, etc. In this approach design starts with bottom level , by inside of a class. Ones A class is implemented, then object of that class is created. A main function is generally also used here like procedure oriented  languages as a starting point, but it’s used only to call the class functions.

Calculate Totient number from given number

Q : Write a program to get Totient number from given number?

[     Totient number = All prime number(M)<given prime number(N)
      l.e. N=10
     M={1,3,5,7}=4

]

Answer : 

/*   ::: Girfa :::

http://girfahelp.blogspot.in/p/c-language.html

program : get all prime number less than given number   */

Symmetric Encryption

 " Data format changed using a secret key and can be decrypted only with this secret key receiver must have the secret key for decrypt message. Symmetric Encryption. " 

Symmetric encryption is the oldest and best-known technique. A secret key, which can be a number, a word, or just a string of random letters, is applied to the text of a message to change the content in a particular way. This might be as simple as shifting each letter by a number of places in the alphabet. As long as both sender and recipient know the secret key,

Bridge : Computer Network

  " Bridge is May be a combination of hardware and software or individual is used to connect two segment of same LAN (Same IP Domain). Bridge decreases the network traffic and also used to connect two different platform LANs like UNIX and Windows. " 

    A network bridge is software or hardware that connects two or more networks so that they can communicate.

    People with home or small office networks generally use a bridge when they have different types of networks but they want to exchange information or share files among all of the computers on those networks.

     Here's an example. Let's say you have two networks: in one, the computers are connected with cables; and in the other, the computers are connected using wireless technology. The wired computers can only communicate with other wired computers, and the wireless computers can only communicate with other wireless computers. With a network bridge, all of the computers can communicate with each other.