我正在做一个学校的项目，我不明白为什么switch语句没有在main中打印。我正在尝试做一个菜单选择，我在另一个项目中使用了相同的代码，它工作得很完美。

char square[] = { 'o', '1', '2', '3', '4', '5', '6', '7', '8', '9' };

int choices, def;
int checkWin();

struct Player
{
    char init[3]; //initials for player
    char xo; //x or o
    int wins; //player wins
    int losses; //player losses
    int ties; //player ties
    int turn; //players turn
};

int checkWin()
{
    if (square[1] == square[2] && square[2] == square[3])
        return 1;

    else if (square[4] == square[5] && square[5] == square[6])
        return 1;

    else if (square[7] == square[8] && square[8] == square[9])
        return 1;

    else if (square[1] == square[4] && square[4] == square[7])
        return 1;

    else if (square[2] == square[5] && square[5] == square[8])
        return 1;

    else if (square[3] == square[6] && square[6] == square[9])
        return 1;

    else if (square[1] == square[5] && square[5] == square[9]) {
        return 1;
    }
    else if (square[3] == square[5] && square[5] == square[7])
        return 1;

    else if (square[1] != '1' && square[2] != '2' && square[3] != '3' &&
             square[4] != '4' && square[5] != '5' && square[6] != '6' &&
             square[7] != '7' && square[8] != '8' && square[9] != '9')
        return 0;

    else {
        return  - 1;
    }
}

void displayBoard()
{
    printf("\n\n\tTic Tac Toe\n\n");

    printf("Player 1 (X)  -  Player 2 (O)\n\n\n");
    //board display
    printf("     |     |     \n");
    printf("  %c  |  %c  |  %c \n", square[1], square[2], square[3]);
    printf("_____|_____|_____\n");
    printf("     |     |     \n");
    printf("  %c  |  %c  |  %c \n", square[4], square[5], square[6]);
    printf("_____|_____|_____\n");
    printf("     |     |     \n");
    printf("  %c  |  %c  |  %c \n", square[7], square[8], square[9]);
    printf("     |     |     \n\n");
}

int main() {
    int player = 1, i, choice;
    char mark;

    switch(choices) {

        case 1:
            printf("\t\t\t1. PLAY\n");
            printf("\t\t\t2. INSTRUCTIONS\n");
            printf("\t\t\t3. STATISTICS\n");
            printf("\t\t\t4. EXIT\n\n");

            printf("\t\t\tENTER A NUMBER (1-4): ");
            scanf("%d", &def);

            if (def == 1) {
                void displayBoard();
            }

            if (def == 2) {
                printf("----INSTRUCTIONS----\n\n");

                printf("To begin the game, select play in the menu.\n");
                printf("This is your board:\n\n");
                printf("----------\n");
                printf("1 | 2 | 3\n");
                printf("----------\n");
                printf("4 | 5 | 6\n");
                printf("----------\n");
                printf("7 | 8 | 9\n");
                printf("----------\n\n");
                printf("Players will take turns inputting their X or O, ('X' or 'O') by entering the number on the board.\n");
                printf("The first player to get three of their letter in a row wins.\n\n");
            }

            if (def == 3) {
                struct Player;
            }

            if (def == 4) {
                fclose;
            } else {
                return 0;
            }

            do {
                displayBoard();
                player = (player % 2) ? 1 : 2;

                printf("Player %d, enter a number:  ", player);
                scanf("%d", &choice);

                mark = (player == 1) ? 'X' : 'O';

                if (choice == 1 && square[1] == '1') {
                    square[1] = mark;
                } else if (choice == 2 && square[2] == '2') {
                    square[2] = mark;
                } else if (choice == 3 && square[3] == '3') {
                    square[3] = mark;
                } else if (choice == 4 && square[4] == '4') {
                    square[4] = mark;
                } else if (choice == 5 && square[5] == '5') {
                    square[5] = mark;
                } else if (choice == 6 && square[6] == '6') {
                    square[6] = mark;
                } else if (choice == 7 && square[7] == '7') {
                    square[7] = mark;
                } else if (choice == 8 && square[8] == '8') {
                    square[8] = mark;
                } else if (choice == 9 && square[9] == '9') {
                    square[9] = mark;
                } else {
                    printf("Invalid move ");
                    player--;
                    getch();
                }
                i = checkWin();

                player++;
            } while (i == -1);
            {
                displayBoard();
            }
            if (i == 1) {
                printf("==>\aPlayer %d win ", --player);
            } else {
                printf("==>\aGame draw");
            }

            getch();
            int selection();
    }
}

Switch语句没有打印出来，我试过移动代码，把它放在它自己的函数里面，所有的一切，我默认把它放在main里面，希望它能打印出来，但是它默认打印井字游戏板，完全跳过了switch语句。