Game 0 Unit 9 of 15 1 hr learning time

The Screen Is a Grid

Place text anywhere with PRINT AT. The Spectrum's screen is a grid 32 columns wide and 24 rows tall, addressed from the top-left — so you can put a label in a corner, the centre, or wherever the layout needs it. The title card finds its spot.

60% of Meet BASIC

So far text has landed wherever the last PRINT left off. Now you take charge of where. The Spectrum's screen is a grid — 32 columns across, 24 rows down — and PRINT AT puts text at any cell you name.

Milestone 1 — place a word

  10 CLS
  20 PRINT AT 10, 13; "Here"

PRINT AT 10, 13; "Here" prints at row 10, column 13 — roughly the middle. The order is row first, then column (down, then across), and both count from 0 at the top-left.

The Spectrum screen showing the word Here near the centre, with the report 0 OK, 20:1.
PRINT AT row, column places text exactly. Row 0 is the top, column 0 is the left — so 10, 13 lands near the middle.

Milestone 2 — address the whole grid

Give the corners and the centre their own PRINT ATs and the grid comes into focus:

Step 2: place text in the corners and the middle
+4-1
11 10 CLS
2- 20 PRINT AT 10, 13; "Here"
2+ 20 PRINT AT 0, 0; "top-left"
3+ 30 PRINT AT 0, 22; "top-right"
4+ 40 PRINT AT 21, 0; "bottom-left"
5+ 50 PRINT AT 10, 13; "middle"
36

Row 0 is the top, row 21 near the bottom (the lowest two rows are kept for the input area), column 0 the left edge, column 31 the right. Each label lands exactly where its numbers put it.

The Spectrum screen showing top-left, top-right, middle and bottom-left each placed at a different position.
The grid, addressed: four labels, four positions. Rows run 0 to 21 for the print area; columns run 0 to 31.

Milestone 3 — the title card finds its spot

Back to the title card. In Unit 3 it printed from the top-left; now you can place it where you want — centred, like a real game's opening screen:

  10 CLS
  20 PRINT AT 8, 11; "MEET BASIC"
  30 PRINT AT 10, 7; "a Spectrum primer"

To centre a line, leave equal space each side: MEET BASIC is 10 characters, so starting at column 11 leaves 11 columns either side of the 32.

The Spectrum screen showing MEET BASIC and a Spectrum primer centred in the upper middle of the screen.
The title card, placed. Next it gets colour, then sound, then movement — but first it needed somewhere to sit.

When it doesn't work

  • The text landed in the wrong place. AT is row, then column — AT 10, 13 is row 10, column 13, not the other way round. A common slip.
  • Integer out of range. A row above 21 or a column above 31 is off the grid. Keep rows 0–21 and columns 0–31.
  • It printed at the top-left anyway. Check the punctuation: PRINT AT row, col; — a semicolon after the position, before the text.

Before and after

You started with text landing wherever the last PRINT left off and finished placing it anywhere on a 32-by-24 grid — corners, centre, a centred title. The idea underneath: PRINT AT row, column addresses the screen as a grid, counting from 0 at the top-left.

Try this

  • Centre your name. Work out the column that centres it and place it mid-screen.
  • A border of dots. Use a FOR loop and PRINT AT to run a row of dots along the top.
  • Stack a menu. Place three options at rows 8, 10 and 12, all at the same column.

What you've learnt

  • The screen is a grid: 32 columns, 24 rows, addressed from 0 at the top-left.
  • PRINT AT row, column; "text" places text exactly — row first, then column.
  • The print area is rows 0–21; the lowest two rows are the input area.
  • Centre a line by leaving equal columns on each side.

What's next

The title card has a place — but it's still grey on grey. In Unit 10 we bring colour: INK, PAPER, BORDER, and a loop that paints the title in every colour at once.