Array length property in Java - Step-by-Step Execution

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Concept Flow - Array length property

Create array

↓

Access length property

↓

Use length value

↓

Perform operations (e.g., loop)

↓

End

This flow shows creating an array, accessing its length property, and using that length to control operations like loops.

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Execution Sample

Java

int[] arr = {10, 20, 30};
int len = arr.length;
System.out.println(len);

This code creates an array, gets its length using the length property, and prints the length.

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Execution Table

Step	Action	Expression Evaluated	Result/Value	Output
1	Create array arr	int[] arr = {10, 20, 30};	arr = [10, 20, 30]
2	Access length property	arr.length	3
3	Assign length to len	int len = arr.length;	len = 3
4	Print length	System.out.println(len);	3	3
5	End	-	-	-

💡 Execution ends after printing the array length.

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Variable Tracker

Variable	Start	After Step 1	After Step 3	Final
arr	null	[10, 20, 30]	[10, 20, 30]	[10, 20, 30]
len	undefined	undefined	3	3

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Key Moments - 3 Insights

▶Why do we use arr.length without parentheses?

▶Can the length of an array change after creation?

▶What happens if we try to access arr.length before creating the array?

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Visual Quiz - 3 Questions

Look at the execution table, what is the value of arr.length at Step 2?

A 0

B undefined

C 3

D null

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Concept Snapshot

Array length property in Java:
- Use arrayName.length (no parentheses) to get size
- Length is fixed after array creation
- Useful for loops and bounds checking
- Example: int len = arr.length;
- Accessing length before array creation causes error

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Full Transcript

This lesson shows how to use the length property of arrays in Java. First, an array is created with three elements. Then, the length property is accessed without parentheses to get the number of elements, which is 3. This value is stored in a variable and printed. The length property is fixed and cannot change after the array is created. Trying to access length before creating the array causes an error. The execution table tracks each step and variable values to help understand the process.