Scrambled Words

This two-player word game presents scrambled five-letter words and challenges each player to reconstruct the original word by typing letters one at a time. The program stores a dictionary of 200 five-letter words as a single concatenated string in lines 780–830, accessing each word with the slice expression `A$(5*Q-4 TO 5*Q)`. A countdown timer starting at 61 ticks down via subroutine calls on each INKEY$ polling loop, with points awarded equal to the remaining time value, rewarding faster answers. The scrambling routine at lines 320–370 destructively marks used character positions with “0” to avoid reuse, building the anagram display left to right. Ten rounds per player are tracked by a single shared counter `S`, with odd values belonging to player 1 and even values to player 2.

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Program Analysis

Program Structure

The program is divided into clearly identifiable functional blocks:

1. Lines 10–90: Title screen and instructions
2. Lines 100–160: Initialisation (scores, player names)
3. Lines 170–217: Turn management and random seeding delay loops
4. Lines 220–370: Word selection and scrambling
5. Lines 376–550: Letter-by-letter input loop with countdown
6. Lines 560–715: Scoring, round display, and game flow
7. Lines 720–725: Game-over handling
8. Lines 730–744: Time-out handler
9. Lines 750–770: Countdown timer subroutine
10. Lines 780–850: Word dictionary data
11. Lines 900–910: Border-drawing subroutine
12. Lines 920–940: Save/run bootstrap

Word Dictionary

All words are stored as a single concatenated string across lines 780–830. Each word is exactly five characters, so word Q is retrieved with the slice A$(5*Q-4 TO 5*Q). The string is built in stages because a single BASIC line cannot hold all ~200 words. A random index Q is chosen at line 220 with INT(200*RND)+1. Note the dictionary contains some duplicates (e.g. “FRONT” appears in both lines 780 and 820, “SWEET” in lines 810 and 820, “FLOAT” in lines 810 and 820, “OTHER” in lines 780 and 820, “LOWER” in lines 780 and 820, “ORDER” in lines 780 and 820, “CARRY” in lines 780 and 820) — the instructions even acknowledge this: “some words may appear more than once.”

Scrambling Algorithm

The scrambling routine (lines 320–370) works destructively on a copy B$ of the chosen word:

• A random position R from 1–5 is chosen.
• If B$(R) is already "0" (previously used), the loop retries at line 330.
• The character is appended to C$ with a trailing space, then the source position is set to "0".
• The original unscrambled word is preserved in D$ for answer checking.

This is a straightforward pick-without-replacement shuffle. For words with repeated letters (e.g. “LEVEL”), the "0" sentinel approach still works correctly because each character position — not character value — is independently nulled.

Countdown Timer

The variable G is initialised to 61 at line 375. Every time an INKEY$ poll returns empty, the subroutine at line 750 is called, which decrements G by 1 and prints the updated value at position AT 2,27. When G reaches 0 or below, execution jumps to line 730 (time-out handler). Because G is also the points awarded on a correct answer, faster solutions yield higher scores — a neat dual-purpose variable.

Input Loop Design

Each of the five letters is handled by a separate, near-identical block (lines 390–550). Each block polls INKEY$ in a tight loop, calling the timer subroutine on each empty read. Letters are printed at fixed screen positions (AT 10,10 through AT 10,18 in steps of 2). There is no backspace facility by design, as stated in the instructions. The small FOR–NEXT loops (e.g. lines 435–436) serve as very brief delays after each keypress is registered.

Letter	Variable	Screen position
1st	V$	AT 10,10
2nd	W$	AT 10,12
3rd	X$	AT 10,14
4th	Y$	AT 10,16
5th	Z$	AT 10,18

Two-Player Turn Tracking

A single shared counter S increments on every completed word (line 580 or 740). Odd values of S represent player 1’s words and even values player 2’s. The test IF S/2=INT(S/2) distinguishes even (player 2) from odd (player 1). After 20 total words (10 each) the game ends. Turn routing after player 2’s word jumps back to line 170 (player 1’s turn label) via line 715, while after player 1’s word it jumps to line 190 (player 2’s turn label) at line 645.

Random Seed Warm-Up

Lines 203–217 use nested FOR–NEXT loops with a fresh RAND call and RND-driven loop counts to consume an unpredictable number of RND iterations before selecting the word. This is a common technique to improve perceived randomness when the hardware RND seed is otherwise predictable at program start.

Notable Bugs and Anomalies

• Line 573 calls GOSUB 900 (border drawing) after a wrong answer, then line 574 prints AT 2,0 and falls through to line 380, which re-displays the scrambled word — this means a wrong-answer retry correctly redraws the border and word without re-scrambling, which is the intended behaviour.
• The variable X is used as both the loop variable in the delay loops (lines 435–436, 465–466, 495–496, 525–526) and as the variable name for the third letter. This is not an error per se — the delay loops use FOR X and NEXT X only for timing and do not need X to retain its value — but it is a potential source of confusion.
• Line 680 prints PRINT AT 3,12;"ROUND ";INT(S/2) for player 2, while line 620 prints INT(S/2)+1 for player 1. This means the round number display for player 2 is one behind; at S=2 (end of round 1), player 2 sees “ROUND 1” while player 1 saw “ROUND 1” too — this is actually consistent. At S=20, lines 673–675 skip the round display entirely.
• The variable Q is reused for both the word index (line 220) and the delay loop counter (lines 635–640, 700–705), which is safe only because the delay loop is not inside the word-selection section.
• Line 572 calls GOSUB 900 before a retry, but line 202 also calls GOSUB 900 at the start of each turn, so the border is correctly maintained throughout.

Subroutine at Line 900

This subroutine draws a simple rectangular border using inverse-video asterisks and spaces via three PRINT AT statements. The border occupies rows 9–11, columns 9–19, providing a visual frame for the timer display and input area. Inverse characters are rendered using the %* and % escape notation in the source.