KwickClips Java · 44 sec · free
Why does a 2D array need two indexes?
Short answer. One for the row and one for the column, like a cinema seat.
Which index comes first?
The row.
A 3 × 3 grid
| Col 0 | Col 1 | Col 2 |
|---|---|---|
| 1 | 2 | 3 |
| 4 | 5 | 6 |
| 7 | 8 | 9 |
Remember
| m[row][col] |
| Both indexes start at 0 |
A cinema seat needs two numbers. So does a two-dimensional array. Rows go across, columns go down. Row zero is one, two, three. Row one is four, five, six. Row two, seven to nine. Row first, then column. Both start at zero.
This clip is from the full lesson: Two-dimensional Arrays and Matrices — 6 minutes, with the tables, the quick answers and the whole lesson in text.
Useful for: ICSE Class 10 Computer Applications, Cambridge IGCSE Grade 9 Computer Science (0478), Cambridge IGCSE Grade 10 Computer Science (0478), Programming All levels Java
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