Concept of Coding & Decoding:

Coding & Decoding topic is very important for all Campus Placements and also for all Competitive exams. Basically, a ‘CODE’ means ‘system of signals’. Therefore, Coding is a method of transmitting a message between the sender and receiver without a third person knowing it. In general, we have several types of problems in this concept. Those are,

1) Letter Coding

2) Number or Symbol Coding

3) Direct Coding

4) Substitution Coding

5) Message Word Coding

Concept 1:

Letter Coding

In this concept, the problems are given in such a way that the letters in the word will be coded with some other letters according to certain logics or patterns. The candidate has to identify the logic or pattern for the given words and apply the similar logic or pattern for the question which he asked and solve the solution accordingly.

Eg: 1) In a certain code , TEACHER is written as VGCEJGT . How is CHILDREN written in that code?

a) EJKNEGTP            b) EGKNFITP                 c) EJKNFGTO              d) EJKNFTGP

2) In a certain code , BREAKTHROUGH is written as EAOUHRBRGHKT . How is DISTRIBUTION written in that code?

a) TISTBUONDIRI                 b) STTIBUONRIDI             c) STTIBUDIONRI            

d) RISTTIBUDION

Concept 2:

Number or Symbol Coding

In this concept, the problems will be given as either in terms of letters in relation with numbers or letters in relation with symbols. For the given letters to numbers or letters to symbols in the question, there will be a certain pattern is applied as like in letter coding. The candidate needs to find that particular pattern and answer the given question accordingly.

In this concept, we are also having another model of problems in which letters or numbers and their respective codes will be given in the form of a table along with certain number conditions applied for that. The candidate needs to understand those conditions and answer the question accordingly.

Eg: 1) If MACHINE is coded as 19 – 7 – 9 – 1 4 – 15 – 20 - 11, how will you code DANGER?

(a) 11 – 7 – 20 – 16 – 11 – 24                 (b) 13 – 7 – 20 – 9 – 11 – 25        

(c) 10 – 7 – 20 – 13 – 11 – 24                 (d) 13 – 7 – 20 – 10 – 11 – 25

2) In a certain code language, STRING is written as % = * - $ ÷ and PRAISE as  ? * @ - % x. How will the word GRAPES be written in that code language?

(a) ÷ * @ x ? %     (b) ÷ @ * ? x %    (c) ÷ * @ ? x %      (d) + * - ? x %   (e) None of these

Concept 3:

Direct Coding

In this concept, as the name itself suggest that it is direct coding. Basically, in the questions he will mention two or more than two words along with its respective codes and he will ask us to find the code for one word which consists of the letters which are already given in the question. Based on those codes the candidate has to answer the question just by substituting the codes directly. Here in this concept, they may use either letters, numbers or symbols in the question.

Eg: 1) If in a certain code, O is written as E, A as C, M as I, S as O, N as P, E as M, I as A, P as N and C as S, then how will COMPANIES be written in that code?

(a) SMINCPAMO                    (b) SEIACPAMO                      (c) SEINCPAMO

(d) SEINCPMIO                        (e) None of these

2) In a code language, TUTORIAL is written as DODNGLCF and DANCE is written as YCJMZ, how can EDUCATION be written in that code?

(a) ZYMODCLNJ                     (b) ZYOMCDLNJ                     (c) ZYOMDCLNJ

(d) ZYOTNLCMD                    (e) None of these

Concept 4:

Substitution Coding

In this concept, the problems are very easy to solve once the candidate understand the concept. Here in this concept, the question will consist of certain words which are substituted with other words and then the question will ask. The candidate has to answer the question with substituted words, but not with exact words.

Eg: 1) If ‘white’ is called ‘blue’, ‘blue’ is called ‘red’, ’red’ is called ‘yellow’, ’yellow’ is called ‘green’, ’green’ is called ‘black’, ‘black’ is called ‘violet’ and ‘violet’ is called ‘orange’, what would be the colour of human blood?

(a) Red             (b) Green          (c) Yellow         (d) Violet          (e) Orange

2) If, in a language, ‘finger’ is called ‘toe’, ‘toe’ is called ‘foot’, ‘foot’ is called ‘thumb’, ‘thumb’ is called ‘ankle’, ‘ankle’ is called ‘palm’ and ‘palm’ is called ‘knee’, then in that language, what will an illiterate man put to mark his signatures?

(a) Toe              (b) Knee            (c) Thumb                     (d) Ankle      

Concept 5:

Message Word Codes

In this concept, in the given question he will mention some words or messages along with coded language but not in respective form. He will ask us to find the code for any word or message by analysing the given messages in a proper manner. To answer the questions related to this model, the candidate must be in a position to analyse the message words in all the statements given in the question. Here, the codes may be either in terms of letters, numbers or symbols. Mostly, he will mention about letters and numbers. Sometimes there is a chance of asking group questions from this concept.

Eg: 1) In a certain language, ’sun shines brightly’ is written as ‘ba lo sul’, ‘houses are brightly lit’ as ‘kado ula ari ba’ and ‘light comes from sun’ as ‘dopi kup lo nor’. What code-words are written for ‘sun’ and ‘brightly’?

(a) ba, sul                      (b) sul, lo                      (c) lo, ba                       (d) ba, lo  

2) Read the information given below to answer the questions that follow:

In a certain code language,

(A) ‘min fin bin gin’ means ‘ trains are always punished’;

(B) ‘gin din cin hin’ means ‘drivers were always punished’;

(C) ‘bin cin vin rin’ means ‘drivers stopped all trains’; and

(D) ‘din kin fin vin’ means ‘all passengers were late’;

‘Drivers were late’ would be written as

(a) min cin din               (b) fin cin din                (c) fin din gin                (d) gin hin mi

Q1. In a certain code language,

‘456’ means ‘cold purify water’

‘689’ means ‘specific cold week’

‘812’ means ‘week day month’

Which digit in that code means ‘specific’?

A) 2                        B) 8                        C) 1                        D) 9                    E) 4

SOLUTION:

In the first and second statements, the common code digit is ‘6’ and the common word is ‘cold’.

Hence, ‘6’ means ‘cold’.

In the second and third statements, the common code digit is ‘8’ and the common word is ‘week’.

So, ‘8’ means ‘week’. Therefore, in the second statement, ‘9’ means ‘specific’.

Answer: D

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