Add Horizontal and Vertical win checking

Adds horizontal and vertical win checking, as well as tests for such
features.

Adds valgrind to the flake.nix

Adds test_connect4 option to Makefile

Makefile

@@ -1,14 +1,16 @@
 CC = gcc
 CFLAGS = -g -Wall -pedantic
 
-connect4.c main.c: connect4.h
+test_connect4.c connect4.c main.c: connect4.h
 
-TARGET = connect4
 CFILES = main.c connect4.c
 OFILES = ${CFILES:.c=.o}
 
 connect4: ${OFILES}
-	$(CC) $(CFLAGS) -o ${TARGET} ${OFILES}
+	$(CC) $(CFLAGS) -o connect4 ${OFILES}
+
+test_connect4: test_connect4.o connect4.o
+	$(CC) $(CFLAGS) -o test_connect4 test_connect4.o connect4.o
 
 clean:
-	rm -r ${TARGET} ${OFILES}
+	rm -r connect4 test_connect4 *.o

connect4.c

@@ -14,7 +14,7 @@ struct Board *make_board(size_t height, size_t width)
   new_board->tile_heights = calloc(width, sizeof(*(new_board->tile_heights)));
   if (!new_board->tile_heights)
     goto out_tile_heights;
-  
+
   new_board->height = height;
   new_board->width = width;
   new_board->next_player = RED;
@@ -28,26 +28,81 @@ out_tilemap:
   return NULL;
 }
 
-int drop_tile(struct Board *board, size_t drop_pos) {
+void free_board(struct Board *board)
+{
+  free(board->tile_heights);
+  free(board->tilemap);
+  free(board);
+}
+
+int check_for_win_horizontal(struct Board *board, size_t pos_i, size_t pos_j)
+{
+  enum Tile current_player = board->next_player * -1;
+  char in_a_row = 1;
+  // Right
+  size_t npos_i = pos_i + 1;
+  while (npos_i < board->width && IDX(npos_i, pos_j, board) == current_player) {
+    in_a_row++;
+    npos_i++;
+    if (in_a_row >= 4)
+      return 1;
+  }
+  // Left
+  npos_i = pos_i - 1;
+  while (npos_i < board->width && IDX(npos_i, pos_j, board) == current_player) {
+    in_a_row++;
+    npos_i--;
+    if (in_a_row >= 4)
+      return 1;
+  }
+  return 0;
+}
+
+int check_for_win_vertical(struct Board *board, size_t pos_i, size_t pos_j)
+{
+  enum Tile current_player = board->next_player * -1;
+  char in_a_row = 1;
+  // Down
+  size_t npos_j = pos_j + 1;
+  while (npos_j < board->height && \
+      IDX(pos_i, npos_j, board) == current_player) {
+    in_a_row++;
+    npos_j++;
+    if (in_a_row >= 4)
+      return 1;
+  }
+  return 0;
+}
+
+int check_for_win(struct Board *board, size_t pos_i, size_t pos_j)
+{
+  if (check_for_win_horizontal(board, pos_i, pos_j))
+      return 1;
+  if (check_for_win_vertical(board, pos_i, pos_j))
+      return 1;
+  return 0;
+}
+
+int drop_tile(struct Board *board, size_t drop_pos)
+{
   if (drop_pos >= board->width)
     return -1;
 
   size_t tower_height = board->height-board->tile_heights[drop_pos]-1;
 
-  if (tower_height < 0)
+  if (tower_height > board->height)
     return -1;
-  
+
   IDX(drop_pos, tower_height, board) = board->next_player;
 
   board->tile_heights[drop_pos]++;
   board->next_player *= -1;
 
-  // Check if player won in separate function
+  return check_for_win(board, drop_pos, tower_height);
-
-  return 0;
 }
 
-void print_board(struct Board *board) {
+void print_board(struct Board *board)
+{
   for (int j = 0; j < board->height; j++) {
     printf("|");
     for (int i = 0; i < board->width; i++) {

connect4.h

@@ -22,6 +22,8 @@ struct Board {
 // Returns a board struct with height and width based on parameters
 struct Board *make_board(size_t height, size_t width);
 
+void free_board(struct Board *board);
+
 // Drops a tile, returns 0 if successful, -1 if error, and 1 if the move won
 int drop_tile(struct Board *board, size_t drop_pos);
 

flake.lock

@@ -18,11 +18,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1720768451,
+        "lastModified": 1720957393,
-        "narHash": "sha256-EYekUHJE2gxeo2pM/zM9Wlqw1Uw2XTJXOSAO79ksc4Y=",
+        "narHash": "sha256-oedh2RwpjEa+TNxhg5Je9Ch6d3W1NKi7DbRO1ziHemA=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "7e7c39ea35c5cdd002cd4588b03a3fb9ece6fad9",
+        "rev": "693bc46d169f5af9c992095736e82c3488bf7dbb",
         "type": "github"
       },
       "original": {

flake.nix

@@ -17,11 +17,13 @@
       git
       gnumake
       gcc
-      gdb
       clang_16
       clang-tools_16
       lld_16
       llvmPackages_16.libllvm
+      
+      valgrind
+      gdb
 
       cmake
       gtest

main.c

@@ -5,12 +5,13 @@
 int main(int argc, char *argv[])
 {
   struct Board *my_board = make_board(6, 7);
-  while (1) {
+  int drop_spot = 0;
+  do {
     print_board(my_board);
-    int drop_spot = 0;
     printf("Where to drop? ");
     scanf("%d",&drop_spot);
-    drop_tile(my_board, drop_spot-1);
+  } while (!drop_tile(my_board, drop_spot-1));
-  }
+  print_board(my_board);
+  printf("Congratulations!");
   return EXIT_SUCCESS;
 }

test_connect4.c

@@ -0,0 +1,60 @@
+#include "connect4.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+void drop_series(struct Board *board, int *positions, size_t psize) {
+  for(int i = 0; i < psize; i++) {
+    drop_tile(board, positions[i]);
+  }
+}
+
+void test_vertical_win(void)
+{
+  struct Board *board = make_board(4,4);
+  int positions[] = {0, 3, 0, 3, 0, 3};
+  drop_series(board, positions, 6);
+  int output = drop_tile(board, 0);
+  assert(output == 1 && "Vertical Win");
+  free_board(board);
+}
+
+void test_left_horizontal_win(void)
+{
+  struct Board *board = make_board(4,4);
+  int positions[] = {0, 0, 1, 1, 2, 2};
+  drop_series(board, positions, 6);
+  int output = drop_tile(board, 3);
+  assert(output == 1 && "Left Horizontal Win");
+  free_board(board);
+}
+
+void test_right_horizontal_win(void)
+{
+  struct Board *board = make_board(4,4);
+  int positions[] = {3, 3, 2, 2, 1, 1};
+  drop_series(board, positions, 6);
+  int output = drop_tile(board, 0);
+  assert(output == 1 && "Right Horizontal Win");
+  free_board(board);
+}
+
+void test_middle_horizontal_win(void)
+{
+  struct Board *board = make_board(4,4);
+  int positions[] = {3, 3, 2, 2, 0, 0};
+  drop_series(board, positions, 6);
+  int output = drop_tile(board, 1);
+  assert(output == 1 && "Middle Horizontal Win");
+  free_board(board);
+}
+
+int main(int argc, char *argv[])
+{
+  test_vertical_win();
+  test_left_horizontal_win();
+  test_right_horizontal_win();
+  test_middle_horizontal_win();
+
+  return EXIT_SUCCESS;
+}