Numeric types (double, single, integer) in MATLAB - Step-by-Step Execution

Concept Flow - Numeric types (double, single, integer)

Start: Assign numeric value

↓

Choose numeric type

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Double

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Store value in memory with type

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Use value in calculations

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End

This flow shows how MATLAB assigns a numeric value to a variable, chooses its type (double, single, or integer), stores it accordingly, and uses it in calculations.

Execution Sample

MATLAB

a = 5;          % default is double
b = single(5);   % single precision
c = int32(5);    % 32-bit integer

This code assigns the number 5 to three variables with different numeric types: double (default), single, and 32-bit integer.

Execution Table

Step	Variable	Value Assigned	Type	Memory Size (bytes)	Notes
1	a	5	double	8	Default numeric type in MATLAB is double precision
2	b	5	single	4	Single precision uses less memory than double
3	c	5	int32	4	Integer type stores whole numbers only
4	Use a + b	10	double	8	Result promoted to double for calculation
5	Use c + 2	7	int32	4	Result remains int32 for calculation
6	End	-	-	-	Execution ends after assignments and calculations

💡 All variables assigned and used; MATLAB ends execution.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
a	undefined	5 (double)	5 (double)	5 (double)	5 (double)
b	undefined	undefined	5 (single)	5 (single)	5 (single)
c	undefined	undefined	undefined	5 (int32)	5 (int32)

Key Moments - 3 Insights

Why does variable 'a' use 8 bytes of memory while 'b' uses 4 bytes?

Because 'a' is of type double which uses 8 bytes for higher precision, while 'b' is single precision which uses 4 bytes, as shown in execution_table rows 1 and 2.

What happens if you add a double and a single type variable?

MATLAB promotes the result to double type for precision, as shown in execution_table row 4 where 'a + b' results in a double.

Can integer variables store decimal numbers?

No, integer types like int32 store only whole numbers. Decimal parts are truncated or cause errors, as implied in execution_table row 3.

Visual Quiz - 3 Questions

Look at the execution_table at step 2. What is the type and memory size of variable 'b'?

A single, 4 bytes

B double, 8 bytes

C int32, 4 bytes

D single, 8 bytes

💡 Hint

Check the 'Type' and 'Memory Size' columns for step 2 in the execution_table.

At which step does MATLAB promote the result to double type during addition?

A Step 3

B Step 4

C Step 5

D Step 2

💡 Hint

Look at the 'Notes' column in execution_table for the step where 'a + b' is calculated.

If variable 'c' was assigned as int16 instead of int32, what would change in the execution_table?

A Type would remain int32

B Value would change from 5 to 16

C Memory size would be 2 bytes instead of 4 bytes

D Variable 'c' would become double

💡 Hint

Check the 'Memory Size' column for int32 and recall int16 uses less memory.

Concept Snapshot

Numeric types in MATLAB:
- Default is double (8 bytes, high precision)
- single uses 4 bytes, less precision
- Integer types (int8, int16, int32, int64) store whole numbers
- Operations may promote types (e.g., single + double -> double)
- Choose type based on precision and memory needs

Full Transcript

This lesson shows how MATLAB handles numeric types: double, single, and integer. Variables 'a', 'b', and 'c' are assigned the value 5 but with different types. Double is default and uses 8 bytes, single uses 4 bytes, and int32 is a 4-byte integer type. When adding double and single, MATLAB promotes the result to double for precision. Integer types store only whole numbers. Memory size and type affect precision and storage. Understanding these helps choose the right type for your data.