c - 函数错误，在 'conflicting type'编译时出现 'C'

Question

我试图用 C 编译我的程序(使用 cygwin)，但在尝试调用 hide_game() 和 show_game() 函数时，我不断收到“冲突类型”和“隐式声明”。如果有人可以帮助我解决这个问题，我将不胜感激!

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <cab202_graphics.h>
#include <cab202_sprites.h>
#include <cab202_timers.h>
#include <curses.h>

bool helpPressed = false;
int was_visible[];
int score = 0;
int lives = 5;
sprite_id ship;
sprite_id ship;
#define S_WIDTH 13
#define S_HEIGHT 6
char * ship_image =
/**/ "      ^      "
/**/ "    /   \\    "
/**/ "  ^/     \\^  "
/**/ "(  .  Y  .  )"
/**/ "(BLACK LIVES)"
/**/ " (  MATTER ) "; 

char * start_msg =
/**/    "----------------------------------------"                                     
/**/    "-         ********************         -"                                     
/**/    "-         The Diamonds of Doom         -"                                     
/**/    "-           ****************           -"                                     
/**/    "-               ********               -"                                     
/**/    "----------------------------------------"
/**/    "-               Controls               -"                                     
/**/    "-             Quit : Q                 -"                                     
/**/    "-             Help : H                 -"                                     
/**/    "-  Move Left/Right : Arrow Keys        -"                                     
/**/    "-     Shoot Bullet : Z X C             -"                                     
/**/    "----------------------------------------"                                     
/**/    "-        Press a key to play...        -"                                     
/**/    "----------------------------------------";

#define MAX_BD 10 
sprite_id Bdiamond[MAX_BD];
#define BD_WIDTH 5
#define BD_HEIGHT 5
char * Bdiamond_image =
/**/    "  0  "
/**/    " 000 "
/**/    "00000"
/**/    " 000 "
/**/    "  0  ";

#define MAX_MD 20 
sprite_id Mdiamond[MAX_MD];
#define MD_WIDTH 3
#define MD_HEIGHT 3
char * Mdiamond_image =
/**/    " 0 "
/**/    "000"
/**/    " 0 ";

#define MAX_LD 40 
sprite_id diamond[MAX_LD];
#define LD_WIDTH 1
#define LD_HEIGHT 1
char * Ldiamond_image =
/**/    "0";

int bullet_index = 0;
#define MAX_BULLET 100 
sprite_id bullet[MAX_BULLET];
#define BULLET_WIDTH 1
#define BULLET_HEIGHT 1
char * bullet_image =
/**/    "o";

char * msg_gameover =
/**/    "###########################"                                         
/**/    "#                         #"                                           
/**/    "#        Game Over        #"                                          
/**/    "#    Play again (y/n)?    #"                                         
/**/    "#                         #"                                        
/**/    "###########################";

double ship_x, ship_y, l_bullet;

bool game_over = false;

void setup_ship(){
    ship = sprite_create( 
        (screen_width() - S_WIDTH) / 2,
        (screen_height() - S_HEIGHT) -3/2,
        S_WIDTH,
        S_HEIGHT,
        ship_image);

    sprite_draw (ship);
}

void setup_diamond() {

    for (int i = 0; i < MAX_BD; i++){
        Bdiamond[i] = sprite_create( 
            rand() % (screen_width()-BD_WIDTH), 
            3,
            BD_WIDTH,
            BD_HEIGHT,
            Bdiamond_image );

        sprite_turn_to (Bdiamond[i], 0.15, 0);
        sprite_turn (Bdiamond[i], rand() % 360 );
        sprite_draw (Bdiamond[i] );
    }
}

void setup_bullet() {
    for( int i = 0; i <=MAX_BULLET; i++){
        bullet[i] = sprite_create(-1, -1, 1 , 1, bullet_image);
    }
}

void wall_check(sprite_id bullet){
        if( sprite_y(bullet) <= 3 && sprite_y(bullet) != -1){
            sprite_move_to(bullet, -1, -1);
            sprite_turn_to(bullet, 0, 0);

        }
    }

bool collision (sprite_id ship, sprite_id Bdiamond2) {
    int lh = round(sprite_x(ship)), rh = lh + sprite_width(ship) -1;
    int lz = round(sprite_x(Bdiamond2)), rz = lz + sprite_width(Bdiamond2) -1;
    int th = round(sprite_y(ship)), bh = th + sprite_width(ship) -1;
    int tz = round(sprite_y(Bdiamond2)), bz = tz + sprite_width(Bdiamond2) -1;

    bool collided = true; 

    if ( bz < th ) collided = false;
    else if ( bh < tz ) collided = false;
    else if ( rz < lh ) collided = false;
    else if ( rh < lz ) collided = false;

    return collided;
}

void process_button() {
    int key = get_char();

    int xh = round(sprite_x(ship));
    int yh = round(sprite_y(ship));

    if ( ( 'a' == key || KEY_LEFT == key ) && xh > 1 ) {
        sprite_move(ship, -1, 0);
        }

    else if ( ( 'd' == key || KEY_RIGHT == key ) && xh < screen_width() - sprite_width(ship) - 1 ) {
        sprite_move(ship, +1, 0);
        }
    if ('x' == key){
        sprite_move(bullet[bullet_index], xh + 7, yh);
        sprite_turn_to(bullet[bullet_index], 0, -0.1);
        bullet_index++;
        }
    if ('z' == key){
        sprite_move(bullet[bullet_index], xh + 3, yh + 2);
        sprite_turn_to(bullet[bullet_index], 0, -0.1);
        bullet_index++;
        }
    if ('c' == key){
        sprite_move(bullet[bullet_index], xh + 11, yh + 2);
        sprite_turn_to(bullet[bullet_index], 0, -0.1);
        bullet_index++;
        }
        if ('h' == key){
            helpPressed = true;
            hide_game();
            sprite_draw(help_msg);
            show_screen();
            wait_char();
            show_game();
        }
}

void hide_game(){
    for( int i= 0; i < MAX_BD; i++ ) {
        if ( Bdiamond[i]->is_visible ) {
            was_visible[i] = 1;
            sprite_hide(Bdiamond[i]);
        }
        else {
        was_visible[i] = 0;
        }
    }
    sprite_hide(ship);
}

void show_game(){
    for( int i= 0; i < MAX_BD; i++ ) {
        if ( was_visible[i] == 1 ) {
            sprite_show(Bdiamond[i]);
        }
        sprite_show(ship);
}

void process_diamond() {
    for( int i= 0; i < MAX_BD; i++ ) {
        if ( Bdiamond[i]->is_visible ) {
            sprite_step( Bdiamond[i] );

            if (collision (ship, Bdiamond[i] )) {
                sprite_hide( Bdiamond[i] );
                lives--; 
            }
        }

        int x_limit = screen_width(), y_limit = screen_height();
        int x = round(sprite_x(Bdiamond[i]));
        int y = round(sprite_y(Bdiamond[i]));
        double dx = sprite_dx(Bdiamond[i]);
        double dy = sprite_dy(Bdiamond[i]);
        if ( (x <= 0) || (x >= screen_width() - sprite_width(Bdiamond[i])) ) dx = -dx;
        if ( (y <= 2) || (y >= screen_height() - sprite_height(Bdiamond[i])) ) dy = -dy;
        if ( dx != sprite_dx(Bdiamond[i]) || dy != sprite_dy(Bdiamond[i]) ) {
        sprite_back(Bdiamond[i]);
        sprite_turn_to(Bdiamond[i], dx, dy);
        }
    }
}

void process_bullet() {
    for( int i = 0; i <= MAX_BULLET; i++){
        sprite_step(bullet[i]);
        wall_check(bullet[i]);

        for(int j= 0; j< MAX_BD; j++)
        {
            if( sprite_visible(Bdiamond[j]) && collision(bullet[i], Bdiamond[j])) {
                sprite_hide(Bdiamond[j]);
                sprite_move_to(bullet[i], -1, -1);
            sprite_turn_to(bullet[i], 0, 0);
            score=score+1;
            }
        }

    }

}


void draw_border(void) {
    int left = 0, right = screen_width() - 1, top = 0, bottom = screen_height() - 1;
    draw_line(left, top, right, top, '#');
    draw_line(left, top + 2, right, top + 2, '#');
    draw_line(left, bottom, right, bottom, '#');
    draw_line(left, top, left, bottom, '#');
    draw_line(right, top, right, bottom, '#');

    int timer = 420;
    draw_formatted(left + screen_width()/3, top + 1, "# Score: %d", score);
    draw_formatted(left + 3, top + 1, "Lives: %d", lives);
    draw_formatted(left + screen_width()*2/3, top + 1, "# Time: %d", timer);
    //draw_double(10, 10, sprite_x(ship));
    //draw_double(10, 11, sprite_y(ship));
    //draw_int(10, 12, sprite_visible(ship));
}

void draw_game() {
    clear_screen();
    draw_border();
    sprite_draw ( ship );

    for (int i = 0; i < MAX_BD; i++ ) {
        sprite_draw(Bdiamond[i] );
    }

    for( int i = 0; i <= MAX_BULLET; i++){
        sprite_step(bullet[i]);
        sprite_draw(bullet[i]);
    }

}

void help() {
    clear_screen();
    int msg_height = 14;
    int msg_width = 40;
    sprite_id helpMsg = sprite_create(
        (screen_width() - msg_width) / 2,
        (screen_height() - msg_height) / 2,
        msg_width, msg_height, start_msg);
    sprite_draw(helpMsg);
    show_screen();
    wait_char();

}

int main () {
    setup_screen();
    help();
    setup_ship();
    setup_diamond(); 
    setup_bullet();
    show_screen();

    while ( ! game_over && helpPressed == false;) {
        process_button();
        process_bullet();
        process_diamond();
        draw_game();
        if ( bullet_index >= 100) {
        bullet_index = 0;
        }
        show_screen();
        timer_pause(10);
    }
    cleanup_screen;     
}

Answer 1

这两个函数需要前向声明，编译器不知道hide_game() or show_game() 什么时候调用这些函数被调用。

在process_button()前添加void hide_game();和show_game();即可解决问题，通常添加这两个声明在文件的顶部。