Battleship with Inter‑Process Communication (IPC)

A terminal‑based Battleship game written in C that showcases:

• Dual‑process architecture (parent + child) communicating over UNIX pipes
• Real‑time ncurses UI with coloured grids
• Save / Load support to resume matches
• Two board sizes – classic 4 × 4 and 8 × 8 with multiple‑cell ships
• Simple AI that alternates between random and tactical shots
• Portable, single‑file project (only main.c) – ideal for coursework or demos

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1. Gameplay

Key	Action
1 / 2	Start a new game on 4×4 or 8×8 board
3	Load the most recent save
4	Quit
p	Pause during a match
m / e	In pause screen: return to menu / exit
(auto)	Game is auto‑saved at the end of every full round

Both processes take turns:

1. Parent: draws UI, decides whose turn it is and flashes the shot result.
2. Child: receives a Fire command, computes coordinates, sends the result back.

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2. Build & Run

sudo apt install build-essential libncurses5-dev   # Debian / Ubuntu
gcc main.c -o battleship -lncurses
./battleship

The game depends only on the POSIX C library and ncurses. Tested on Linux 5.10+ and macOS Ventura (clang).

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3. File layout

main.c         ← complete source (≈900 loc)
save.dat       ← auto‑generated binary save file
README.md      ← you‑are‑here

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4. Code architecture

4.1 Data model

typedef struct {
    char grid[8][8];        // own fleet
    char opponent_grid[8][8];
    int  hits;
    int  total_ship_cells;
    int  score;
    int  last_hit_row, last_hit_col; // AI memory
} Player;                                 

• EMPTY, SHIP, HIT, MISS glyphs keep the UI simple.
• Total ship cells let us detect victory in O(1).

4.2 Process & IPC flow

┌────────────┐     pipe[0] (parent→child)       ┌────────────┐
│  Parent    │ ───────────────────────────────► │   Child    │
│ UI + menu  │ ◄─────────────────────────────── │ AI logic   │
└────────────┘  pipe[1] (child→parent)          └────────────┘

Commands:

Byte	Direction	Payload
'I'	P → C	initial state (board, players)
'F'	P → C	“fire for current player”
'Q'	P → C	quit child
structs	C → P	shot coords, hit flag, updated players, game‑over flag

The parent forks exactly once at launch; subsequent menu returns do not create new children, keeping resources tidy.

4.3 AI strategy

• If the previous shot was a hit, try the four orthogonal neighbours (strategic_fire).
• Otherwise fall back to uniform random selection. For 4×4 boards, a pure random shooter is used.

4.4 Persistence

void save_game(Player *p1, Player *p2) {
    FILE *f = fopen("save.dat","wb");
    fwrite(&grid_size, sizeof(int), 1, f);
    fwrite("P1",2,1,f); fwrite(p1,sizeof(Player),1,f);
    fwrite("P2",2,1,f); fwrite(p2,sizeof(Player),1,f);
}

Binary blob saves are tiny (< 3 kB) and loaded via load_game with sanity checks (player tags, end‑of‑game detection).

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5. Extending the project

• Human vs Human / Network play – swap pipes for sockets.
• Better AI – add probability heat‑maps or hunt/target modes.
• Resizable boards – make grid_size dynamic, allocate grids.
• Cross‑platform TUI – switch to ncursesw for Unicode ships 🔱.

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6. Troubleshooting

Symptom	Fix
error: curses.h: No such file	Install libncurses5-dev (Deb/Ubuntu) or brew install ncurses (macOS)
Window flickers / no colours	Ensure $TERM supports colour (e.g. xterm-256color)
Save won’t load	Delete save.dat if format changed after code edits

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7. License

This sample README leaves the choice to you. Typical options:

SPDX-License-Identifier: MIT

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8. Acknowledgements

Created as a university IPC assignment; thanks to the ncurses community for the timeless TUI library.

Enjoy sinking ships! 🎯

9. Images From the Game