today

week-047.md

@@ -0,0 +1,116 @@
+## [DAY-344] pointers
+
+Add check_win function to the following tic tac toe game:
+
+```
+#include <stdio.h>
+struct board {
+    char a0;
+    char a1;
+    char a2;
+    char b0;
+    char b1;
+    char b2;
+    char c0;
+    char c1;
+    char c2;
+};
+
+struct user_input {
+    char row;
+    char col;
+};
+
+void board_print(struct board game) {
+    printf("  a b c\n");
+    printf("0 %c %c %c\n", game.a0, game.b0, game.c0);
+    printf("1 %c %c %c\n", game.a1, game.b1, game.c1);
+    printf("2 %c %c %c\n", game.a2, game.b2, game.c2);
+    printf("\n");
+}
+
+int board_set(struct board *game, char symbol, struct user_input ui) {
+    int valid_move = 1;
+    if (ui.col == 'a' && ui.row == '0') {
+        game->a0 = symbol;
+    } else if (ui.col == 'a' && ui.row == '1') {
+        game->a1 = symbol;
+    } else if (ui.col == 'a' && ui.row == '2') {
+        game->a2 = symbol;
+    } else if (ui.col == 'b' && ui.row == '0') {
+        game->b0 = symbol;
+    } else if (ui.col == 'b' && ui.row == '1') {
+        game->b1 = symbol;
+    } else if (ui.col == 'b' && ui.row == '2') {
+        game->b2 = symbol;
+    } else if (ui.col == 'c' && ui.row == '0') {
+        game->c0 = symbol;
+    } else if (ui.col == 'c' && ui.row == '1') {
+        game->c1 = symbol;
+    } else if (ui.col == 'c' && ui.row == '2') {
+        game->c2 = symbol;
+    } else {
+        valid_move = 0;
+    }
+    return valid_move;
+}
+
+struct user_input get_user_input(char symbol) {
+    struct user_input ui = {0};
+    printf("%c> ", symbol);
+    ui.col = getchar();
+    ui.row = getchar();
+    getchar(); // ignore the new line
+    return ui;
+}
+
+void toggle_symbol(char *symbol) {
+    // if the symbol is X, set it to 0, if its 0, set it to X
+    if (*symbol == 'X') {
+        *symbol = '0';
+    } else {
+        *symbol = 'X';
+    }
+}
+
+int main(void){
+    char current_symbol = 'X';
+    struct board game_board = {
+        .a0 = '-',
+        .a1 = '-',
+        .a2 = '-',
+        .b0 = '-',
+        .b1 = '-',
+        .b2 = '-',
+        .c0 = '-',
+        .c1 = '-',
+        .c2 = '-',
+    }; 
+
+    while(1) {
+        board_print(game_board);
+        struct user_input input = get_user_input(current_symbol);
+        if (board_set(&game_board, current_symbol, input)) {
+            // only change the symbol if the move is valid
+            toggle_symbol(&current_symbol);
+        }
+        // HOMEWORK:
+        // write check_win(game_board) function that checks if there is a winner
+        // if there is a winner print "X WIN!" if X wins or "0 WIN" if 0 wins, and break to exit the while loop
+        // check the board_set function for inspiration
+        /*
+            example breaking out of a loop:
+            while (1) {
+                if (something) {
+                    break;
+                }
+            }
+        */
+    }
+}
+```
+
+> We spent 1 hour or so discussing pointers and disecting the code
+
+![game-344](./screenshots/game-344.svg)
+<img src="./screenshots/game-344.svg">