Question Constellation Sign up for free AQA · GCSE · Computer Science · Higher
Interpreting a sliding-puzzle program
getTile(row, column) returns the tile value on the 3 x 3 board in position (row, column). The blank space is represented by the value 0.
| int ref1, ref2; |
| for (int i = 0; i < 3; i++) |
| { |
| for (int j = 0; j < 3; j++) |
| { |
| if (getTile(i, j) == 0) |
| { |
| ref1 = i; |
| ref2 = j; |
| } |
| } |
| } |
| row \ column | 0 | 1 | 2 |
|---|---|---|---|
| 0 | 4 | 7 | 6 |
| 1 | 3 | 8 | 1 |
| 2 | 0 (blank) | 5 | 2 |
State the purpose of the program in Figure 16.
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Marking points
- 1 States that the program locates or stores the coordinates of the blank (0) position.
Full-mark answer
It finds and stores the row and column coordinates of the blank space.
Why this answer loses marks
It checks whether the board contains a blank space.
The program does more than detect the blank: it records the position needed by later board operations.