KwickClips Java · 43 sec · free
What changes between row sums and column sums?
Short answer. Which loop is on the outside.
How many loops do the diagonals need?
One, because a single counter gives both indexes.
Which loop?
| Sum | Loop order |
|---|---|
| Row sum | row outside |
| Column sum | column outside |
| Left diagonal | m[i][i] |
| Right diagonal | m[i][n-1-i] |
Remember
| Reset sum for each row |
| Diagonals need one loop |
Row sum, column sum, two diagonals. Which loop goes where? Row sums loop rows outside. Column sums loop columns outside. Left diagonal repeats one index. Right uses N minus one. Reset the sum each row. Diagonals need one loop.
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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