Cricket

This program implements a two-team text cricket game where players deliver a ball by pressing “7” and attempt to hit it with “5” (off-side) or “8” (on-side). The difficulty level (1–3) controls the speed of the ball’s on-screen animation by varying the loop count in the FOR/NEXT delay at lines 120–122. Dismissal outcomes include being bowled (ball landing on the stumps at column B), caught behind (wrong-side shot), caught (random fielder), or dropped. The scoreboard uses a field diagram drawn with “O” and “A” characters to represent fielders, and the innings subroutine at 8505 also sets key variables M, A, and B used throughout the game.

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Program Analysis

Program Structure

The program is divided into several functional blocks:

• Lines 3–27: Initialisation, key legend display, difficulty selection, and team name input.
• Lines 28–76: Innings setup — selects which team bats, prints innings header, then jumps into the main input loop.
• Lines 95–1250: Ball delivery animation loop — moves a * up the screen, optionally deflecting it laterally at step 10.
• Lines 1300–1308: Bowled dismissal handling.
• Lines 2000–2250: Fielding outcomes — caught or dropped, chosen randomly.
• Lines 3000–3035: Caught-behind dismissal.
• Lines 4500–5000: Delivery trigger — waits for key “7” before launching the ball.
• Lines 5005–6095: Shot trajectory calculation and run scoring.
• Lines 6095–8000: Scoreboard update and wicket/innings check.
• Lines 8200–8500: Innings end, next innings, and match end handling.
• Lines 8505–8620: Field-drawing subroutine and wicket-fall animation.
• Lines 8630–8680: Match result and winner announcement.
• Lines 8680–8700: CLEAR / SAVE / RUN block for saving the program.

Difficulty and Timing

Difficulty is selected as 1–3 and mapped to variable P at lines 15–17. P is used as the upper bound of an inner delay loop at lines 120–122: difficulty 1 gives P=3 (slow), difficulty 2 gives P=1 (medium), and difficulty 3 gives P=-1 (the FOR loop body executes zero times, giving the fastest ball). This is a concise way to scale animation speed without separate code paths.

Ball Delivery Animation

The delivery loop runs from N=1 to 20 (line 115), printing and erasing * at PRINT AT X,Y, moving X up the screen by one row each iteration. At N=10 a lateral offset Q=INT(RND*5-3) is added to Y, simulating swing or spin. At N=12 the batting window opens: pressing “5” or “8” depending on which side the ball is on routes to line 5001 (shot), while the wrong-side key routes to line 3000 (caught behind). Pressing “0” before step 12 (line 140) advances N to 13, acting as a leave/defensive shot.

Shot and Run Calculation

When a shot is played, lines 5005–5007 save the ball’s final position in C and D, then choose a random trajectory direction H (1–4) and a distance variable S (0–14). The ball is then animated in one of four diagonal directions across the field. Specific coordinate pairs at lines 6000–6015 represent fielding positions; hitting one triggers the caught/dropped subroutine at line 2000. At the end of the ball’s travel, S is mapped to runs by a series of range checks (lines 6061–6078), giving 1, 2, 3, 4, or 6 runs.

Field Drawing Subroutine

The subroutine at line 8505 draws the fielding positions using pairs of “O” (head) and “A” (body) characters at fixed PRINT AT coordinates. It also sets three variables critical to the game: M=17 (bowler column), A=5 (stumps row), and B=15 (stumps column). The stumps are drawn at line 8525 as "II" at rows A and 21. This dual role — rendering and variable initialisation — is a common space-saving idiom.

Wicket-Fall Animation

Lines 8569–8620 handle a wicket animation: the bowler figure is shown with "O"/"X" at column M, then M is decremented 17 times in a loop, walking the figure across the screen. Variables I and U are assigned inside the loop (lines 8600 and 8607) but never used for any visible effect, suggesting leftover or placeholder code. The routine ends with STOP at line 8620, which appears to be a bug — execution should return to the caller after the animation, but instead halts the program.

Bugs and Anomalies

• Line 85 vs 5001: Line 140 jumps to GOTO 85 (no-shot leave), but line 150/155 jump to GOTO 5001 for a valid shot. Line 5001 does not exist; execution falls through to line 5005. This is intentional fall-through, not a bug.
• Line 85 missing: GOTO 85 at line 4510 targets a non-existent line. Execution falls through to line 95, resetting K=0 — effectively restarting the delivery cycle. This is a deliberate technique.
• Line 860 placement: LET TT=2 at line 860 sits inside the delivery animation loop between lines 155–1200 and is reached on every delivery. TT is supposed to track the innings number, but it is set to 2 unconditionally here — meaning the second-innings flag is set on the very first delivery, breaking the innings logic at line 31.
• Line 8620 STOP: The wicket-fall subroutine ends with STOP rather than RETURN, halting the game after every dismissal. Combined with the missing GOSUB 8555 targets (line 8555 does not exist), dismissal handling is effectively broken.
• Line 8650 uses Y(1): The win calculation references Y(1), which is undefined — T(1) was clearly intended, giving the wrong result or a variable error.
• Variable D reused: D is used both for difficulty (lines 13–17) and for the ball’s column position during shot animation (line 5006 onwards), causing the difficulty value to be overwritten mid-game.

Variable Summary

Variable	Purpose
D	Difficulty level (1–3); also reused as ball column in shot animation
P	Delay loop limit (speed control)
T(O)	Score for each team (array of 2)
H$(O)	Team names (2×12 string array)
W	Wickets fallen
R	Runs scored from last shot
Z	Runs since last wicket (partnership)
X,Y	Ball row/column during delivery animation
C,D	Ball row/column during shot animation
M	Bowler/mid-wicket column
B	Stumps column (set by subroutine at 8505)
S	Random shot distance, mapped to runs
TT	Innings counter (1 or 2)
O	Current batting team index (1 or 2)