AP CSA Unit 4 Day 9: 2D Array Column Major Traversal
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Unit 4, Data Collections • Cycle 2
Day 9 Advanced Practice • Harder Difficulty
Focus: 2D Array Column-Major Traversal
Hard
2D Array Column-Major Traversal
Advanced Practice Question
Format: 2D Array Column-Major Traversal
What is the output?
What is the output?
int[][] grid = {
{1, 2, 3},
{4, 5, 6}
};
for (int c = 0; c < grid[0].length; c++) {
for (int r = 0; r < grid.length; r++) {
System.out.print(grid[r][c] + " ");
}
}
Difficulty: Hard |
Topic: 2D Array Column-Major Traversal |
Cycle: 2 (Advanced)
Why This Answer?
Outer loop iterates columns (c=0,1,2). Inner loop iterates rows (r=0,1). Prints: grid[0][0]=1, grid[1][0]=4, grid[0][1]=2, grid[1][1]=5, grid[0][2]=3, grid[1][2]=6.
Common Mistake
Watch Out!
Confusing row-major (rows outer) with column-major (columns outer) order.
AP Exam Strategy
Column-major: outer loop = columns, inner loop = rows. Processes down each column.
Master This Topic
This Cycle 2 HARD question tests 2d array column-major traversal. Review Unit 4 concepts to build mastery of data collections.
- Understanding 2d array column-major traversal
- Tracing code execution accurately
- Avoiding common pitfalls
Ready for More Challenges?
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