Number literal formats (underscore, hex, binary) in Kotlin - Step-by-Step Execution

Concept Flow - Number literal formats (underscore, hex, binary)

Start

↓

Read number literal

↓

Check for underscores

| Yes↓

Ignore underscores

↓

Check for prefix

↓

Parse as hex

↓

Parse as decimal

↓

Store value

↓

End

The program reads a number literal, ignores underscores, detects if it's hex or binary by prefix, parses accordingly, and stores the value.

Execution Sample

Kotlin

val a = 1_000
val b = 0x1F
val c = 0b1010

Defines three numbers: decimal with underscores, hexadecimal, and binary.

Execution Table

Step	Literal	Underscores Removed	Prefix Detected	Parsed Value	Action
1	1_000	1000	None	1000	Parsed as decimal
2	0x1F	0x1F	0x (hex)	31	Parsed as hexadecimal
3	0b1010	0b1010	0b (binary)	10	Parsed as binary
4	-	-	-	-	End of literals

💡 All literals processed and parsed to decimal values.

Variable Tracker

Variable	Initial	After Step 1	After Step 2	After Step 3	Final
a	undefined	1000	1000	1000	1000
b	undefined	undefined	31	31	31
c	undefined	undefined	undefined	10	10

Key Moments - 3 Insights

Why do underscores not affect the number's value?

Underscores are ignored during parsing as shown in step 1 of the execution_table where '1_000' becomes '1000'. They are just for readability.

How does the program know to parse '0x1F' as hexadecimal?

The prefix '0x' signals hexadecimal parsing, as shown in step 2 of the execution_table.

What happens if a number starts with '0b'?

It is parsed as binary, like in step 3 where '0b1010' becomes decimal 10.

Visual Quiz - 3 Questions

Look at the execution_table, what is the parsed value of '0x1F' at step 2?

A 31

B 1F

C 0x1F

D 15

💡 Hint

Check the 'Parsed Value' column in row for step 2.

At which step does the program remove underscores from the literal?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'Underscores Removed' column in the execution_table.

If the literal was '0b1101_0010', how would the parsed value change compared to '0b1010'?

A It would be 210

B It would be 162

C It would be 10

D It would be 11010010

💡 Hint

Binary '0b11010010' equals decimal 210, but underscores are ignored, so check binary to decimal conversion.

Concept Snapshot

Number literals can include underscores (_) for readability.
Hexadecimal numbers start with '0x' and use digits 0-9 and letters A-F.
Binary numbers start with '0b' and use digits 0 and 1.
Underscores are ignored when parsing.
All literals convert to decimal values internally.

Full Transcript

This example shows how Kotlin reads number literals with underscores, hexadecimal, and binary formats. First, underscores are removed to simplify the number. Then, the program checks if the number starts with '0x' for hex or '0b' for binary. It parses accordingly: hex numbers convert from base 16, binary from base 2, and others as decimal. The parsed values are stored as normal decimal numbers. This helps write numbers clearly without changing their value.