Coding - Decoding of Reasoning - Introduction

Friends, today we shall discuss about the Coding and Decoding type questions of Reasoning section. There are different types of Coding and Decoding questions are there, before going into details lets first understand what is meant by coding and decoding. 

Coding : A particular code or pattern is used to express a word in English language to express it as a different word. The coded word itself does not make any sense unless we know the code, i.e., unless we know the pattern or code that has been followed. 

Decoding : Decoding refers to the process of arriving at the equivalent English word from the code word given. Hence, we can look at two broad categories of questions in coding-decoding. 

1st Category :

In the 1st category of questions, a particular code is given and on the basis of this given code, we have to find out how another word (in English Language) can be coded. The correct code for the given word has to be selected from the answer choices on the basis of the code given in the question. 

Ex : In certain code if the word "VIRTUAL" is coded as "UHQSTZK", then in this code, how is the word "PAINFUL" coded?

Solution :

By observation, we can find that in coding "VIRTUAL" as "UHQSTZK", each letter in the given word has been replaced by the letter that comes immediately before it in the English alphabet. Using this code, if we now have to code "PAINFUL", we need to replace each letter of the word with the letter that comes before it in the English alphabet. Thus the code will be "OZHMETK".

Note : Here, it can be seen form the example, we treat the English alphabet in a circular fashion. i.e., the letter that comes after Z is A. Similarly, the letter that comes before A is Z.

2nd Category :

In the second category of questions, a particular code is given and on the basis of this given code, we have to find out the equivalent word in English language for a word given coded form. The correct word (in English Language) for the given coded word has to be selected from the answer choices on the basis of the code given in the question. 

Ex :  In a particular Code, if the word :SYSTEM" is coded as "UAUVGO", then in teh same code, what does "HCUJKQP" stand for?

Sol : Here, we can observe that each letter in the given word is replaced by the second letter that comes after it in the English alphabet to give us the word in coded form. Hence, to know what "HCUJKOP", we should replace each letter by a letter which second letter before it in the English alphabet. This gives us the word "FASHION".

The first step to be taken in solving questions in coding - decoding is to crack the code. To do this, it will be helpful to understand the broad types of codes that are used. Ofcourse, the number of codes that can be created and used are infinite but one can always keep the commonly used codes in mind. Secondly, practice will make a student much more comfirtable and conversant with these types of questions. 

Some of the more commonly used codes to represent letters of the alphabets in coding decoding problems are

• Use the letter that comes one or any fixed number of places before it in the alphabet. 
• Use a letter as many places from the end of the alphabet as the original letter is from the begining of the alphabet.
• Each vowel may be replaced by the next vowel that comes in the alphabet and each consonant by another consonant following certain pattern with reference to the consonant under consideration. 
• Use one code for all the letters in even places in the given word and a different code for letters n the odd places in the given word to give a new word.
• The same letters in the given word may be used in a cyclic or in some other order to give the coded word.
• Some numerical values can be attributed to the letters of the word based on the letter positions in the alphabet.
• Combination of two or more of the above ways of coding.