2D array traversal patterns

Traversing Every Element

Purpose: Visit every single value in the 2D array.

Use when:

• Printing all values

• Checking every element

• General traversal

Row-by-Row Processing

Purpose: Process one whole row at a time.

Use when:

• Finding row sums

• Finding averages per row

• Comparing rows

Column-by-Column Processing

Purpose: Process one column at a time.

Use when:

• Finding column sums

• Vertical calculations

• Spreadsheet-style problems

Searching

Purpose: Look for a target value.

Use when:

• Checking if something exists

• Finding a specific number

• Boolean search questions

Counting with Condition

Purpose: Count elements that satisfy a condition.

Use when:

• Counting evens

• Counting positives

• Counting values greater than something

Neighbor Checking

Purpose: Check values around a position.

Use when:

• Grid problems

• Game boards

• Maze problems

• Minesweeper-style questions

Creating and Filling

Purpose: Create a new 2D array and assign values.

Use when:

• Initializing arrays

• Building patterns

• Generating tables

Enhanced For Loop

Use when:

• Only reading values

• Printing elements

• Simple traversal

How to access one element?

arr[row][col]

Number of rows

arr.length

Number of columns

arr[row].length