Give the main disadvantage of floating point representation.

Most floating point values are approximations, so small errors accumulate over many operations. Arithmetic is also slower and needs more complex circuitry.

Which representation suits a bank balance held in pence, and why?

An integer count of pence is the right choice, because every value must be exact. Floating point rounding could lose fractions of a penny over many transactions.

Which representation suits a scientific measurement such as 6.02 × 10²³?

Floating point is needed, because the magnitude is far beyond any practical integer range. The mantissa keeps the significant figures while the exponent carries the size.

Eduqas A-Level Computer Science A500QS

Data Structures: Arrays, Records and Hash Tables

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Boolean Logic and Simplification

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Recursion and Modular Programming

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Number Systems and Binary Arithmetic

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Data Types, Characters and Floating Point

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The Operating System and Its Modes

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Data Types, Characters and Floating Point

Integer and floating point compared

3 things to know
Component 2

Overview

Exactness and simple arithmetic on one side; fractions and enormous magnitudes on the other, bought at the price of approximation.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Evaluation

Give the main advantage of integer representation.

Evaluation

Give the main disadvantage of integer representation.

Evaluation

Give the main advantage of floating point representation.

Questions from this subtopic

Each one with the model answer underneath.

1
Give the main advantage of integer representation.
Model answer
An integer is stored exactly, with no rounding error at all. Integer arithmetic is also faster and uses simpler hardware.
2
Give the main disadvantage of integer representation.
Model answer
An integer cannot hold a fractional part, so 7 divided by 2 loses the half. The range is also limited by the word length.
3
Give the main advantage of floating point representation.
Model answer
A floating point format covers a very wide range of magnitudes in a fixed word length. Fractional values can be held to a useful number of significant figures.
4
Give the main disadvantage of floating point representation.
Model answer
Most floating point values are approximations, so small errors accumulate over many operations. Arithmetic is also slower and needs more complex circuitry.
5
Which representation suits a bank balance held in pence, and why?
Model answer
An integer count of pence is the right choice, because every value must be exact. Floating point rounding could lose fractions of a penny over many transactions.
6
Which representation suits a scientific measurement such as 6.02 × 10²³?
Model answer
Floating point is needed, because the magnitude is far beyond any practical integer range. The mantissa keeps the significant figures while the exponent carries the size.

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