ISRO | ISRO CS 2011 | Question 8

What is the decimal value of the floating-point number C1D00000 (hexadecimal notation)? (Assume 32-bit, single precision floating point IEEE representation)
(A) 28
(B) -15
(C) -26
(D) -28


Answer: (C)

Explanation: Floating Point number in Hexadecimal = C1D00000
Floating Point number in Binary = 1100 0001 1101 0000 0000 0000 0000 0000
In 32-bit, single precision floating point IEEE representation, first MSB represents sign of mantissa: 1 is used to represent a negative mantissa and 0 for a positive value of mantissa, next 8 bits are for exponent value and then 23 bits represents mantissa.

Value of exponent = 131-127 = 4
Mantissa = -1.101000000...0
Floating point number = -1.10100...0000 x 24
                      = -11010
                      = -26

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