Study Material for Reasoning : Codining Decoding


CODING and DECODING

Coding and Decoding
Coding and Decoding is the method used for transmitting a message from sender to receiver that no third party can understand it. Coding and Decoding can be done in two ways:
(1)   Letter Coding
(2)   Number Coding

LETTER CODING
Some Important methods used in Letter Coding

Method 1:  Moving a letter forward
If the word NELLORE is coded as OFMMPSF, then coded word for HYDERABAD is
Answer: IZEFSBCBE
Explanation: Each letter is moved one step forward in the word-NELLORE, you can obtain the corresponding word- OFMMPSF as  N -> O,E ->F,L -> M,L -> M,O->P,R->S and E->F. Similarly, HYDERABAD can be coded as IZEFSBCBE.

Method 2: Moving a letter backward
If the word CHAIR is coded as BGZHQ, then coded word for BENCH is
Answer: ADMBG
Explanation: Each letter is moved one step backward in the word- CHAIR, you can obtain the corresponding word- BGZHQ as B -> A,   E -> D,N -> M,C -> B and H ->G. Similarly,
BENCH can be coded as ADMBG

Method 3: Reversing the word
If the word MADAM is coded as MADAM, then coded word for LEVEL is
Answer: LEVEL
Explanation:   Reverse order for MADAM is MADAM. Similarly for LEVEL, it is LEVEL.

Method 4: Reversing the word and moving one step forward
If the word INTERNET is coded as UFOSFUOJ, then coded word for MODEM is
Answer: NFEPN
Explanation: Given word INTERNET should be written in reverse order first i.e. TENRETNI and then each letter should be moved one step forward i.e. T->U, E->F . . . .N->O and I->J and finally it becomes as UFOSFUOJ. Similarly MODEM first appears as MEDOM and then becomes as NFEPN.

Method 5: Reversing the word and moving one step backward
If the word PERMUTATIONS is coded as RMNHSZSTLQDO, then coded word for COMBINATIONS is
Answer: RMNHSZMHALNB
Explanation:   Given word PERMUTATIONS should be written in reverse order first i.e. SNOITATUMREP and then each letter should be moved one step backward i.e. S->R, N->M. . . .E->D and P->O and finally it becomes as RMNHSZSTLQDO. Similarly COMBINATIONS first appears as SNOITANIBMOC and then becomes as RMNHSZMHALNB.

Method 6: Reversing all letters except first and last
If the word PROCESSOR is coded as POSSECORR, then coded word for KEYBOARD is
Answer:  KRAOBYED
Explanation: In the given word, first and last letters will remain same and remaining letters are written in reverse order. Then PROCESSOR -> POSSECORR. Then KEYBOARD becomes KRAOBYED

Method 7: Moving odd letters a step forward, without any change in even letters
If the word POTATO is coded as QOUAUO, then coded word for BRINJAL is
Answer: CRJNKAM
Explanation: In the given word POTATO, odd letters are moved a step forward while the even letters remains same i.e. P->Q,T->U and T->U, the new word becomes as QOUAUO. Similarly BRINJAL becomes as CRJNKAM

Method 8: Moving even letters a step forward, without any change in odd letters
If the word CHEMICAL is coded as CIENIDAM, then coded word for MEDICAL is
Answer: MFDJCBL
Explanation: In the given word CHEMICAL, even letters are moved a step forward while the odd letters remains same i.e. H->I,M->N, C->D and L->M, the new word becomes as CIENIDAM. Similarly MEDICAL becomes as MFDJCBL.

Method 9: Moving even letters a step forward and odd numbers a step backward
If the word QUESTION is coded as PVDTSJNO, then coded word for ANSWER is
Answer: ZORXDS
Explanation: In the given word QUESTION, if even letters are moved one step forward (U->V, S->T, I->J and N->O) and odd letters moved one step backward (Q->P, E->D, T->S and       O>N), then the word QUESTION becomes as PVDTSJNO. Similarly, ANSWER becomes as ZORXDS.

Method 10: Moving odd letters a step forward and even numbers a step backward
If the word PENCIL is coded as QDOBJK, then coded word for ERASER is
Answer: FQBRFQ
Explanation: In the given word PENCIL,  if odd letters are moved one step forward (P->Q, N->O and I->J) and even letters moved one step backward (E->D, C->B and L>K),then the word PENCIL becomes as QDOBJK. Similarly, ERASER becomes as FQBRFQ.



NUMBER CODING:
Sample Problems
1. If Rose is coded as 6821, Chair is coded as 73456, preach is coded as 961473 and then code for SEARCH is
Answer: 214673
Explanation:  compare the code of each letter in all the above words given, and then form  code for SEARCH i.e. let us take letter E, its code is 1 in both Rose (6821) and Preach (961473)
S -> 2
E -> 1
A -> 4
R -> 6
C -> 7
H -> 3


2. If exam is coded as 5234 and sample is coded as 134675 and then code for EXAMPLE is
Answer: 5234675
Explanation:  From the given two words exam (5234) and sample (134675), we can code EXAMPLE as 5234675