COA

 

BCD (Binary Coded Decimal)

Definition:
BCD is a numeric representation where each decimal digit (0–9) is represented separately in binary form (4 bits).

Examples:

·         Decimal 5 → 0101 (in BCD)

·         Decimal 27 →

o    2 → 0010

o    7 → 0111

o    So, 0010 0111

·         Decimal 93 →

o    9 → 1001

o    3 → 0011

o    So, 1001 0011

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Types of BCD:

1.      8421 BCD (most common) – weights are 8,4,2,1
Example: 7 → 0111 (4+2+1=7)

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Advantages of BCD:

·         Easy conversion between decimal and binary.

·         Useful in financial/decimal calculations (ATM, calculators).

Disadvantages of BCD:

·         Takes more storage than pure binary.
(e.g., Decimal 99 = 2 digits → needs 8 bits in BCD, but only 7 bits in binary).

·         Arithmetic is more complex.

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✅ Quick Summary:

·         Floating Point → Used for real numbers, fractions, scientific calculations.

·         BCD → Used for exact decimal digit storage (financial applications).