c++ - 未解析的外部符号 ""在函数 _main 中引用

Question

我在程序/游戏的主函数中调用了三个函数时遇到问题:initEnemy、drawEnemy 和 updateEnemy。每个在运行时都附有此错误:“错误 LNK2019:未解析的外部符号“...”在函数 _main 中引用”

函数调用在我的主函数中用红色下划线标出，当突出显示时说:“错误:重载函数的多个实例“...”与参数列表匹配:”

如果有人能帮助我理解问题所在，将不胜感激。谢谢。

#include <allegro5\allegro.h>
#include <allegro5\allegro_primitives.h>
#include <allegro5\allegro_font.h>
#include <allegro5\allegro_ttf.h>
#include <allegro5\allegro_image.h>
#include <iostream>
#include <stdio.h>
#include "objects.h"
#include <cstdlib>
#include <random>
using namespace std;

//GLOBALS==============================
const int WINDOW_WIDTH = 1000;
const int WINDOW_HEIGHT = 675;
const int NUM_BULLET = 5;
const int NUM_ENEMY = 5;

enum STATE{TITLE, PLAYING, LOST};
enum KEYS{UP, DOWN, LEFT, RIGHT, SPACE, W, A, S, D};
bool keys[9] = {false, false, false, false, false, false, false, false, false};

int vx = 25;
int shipvy = 15;
int runnervy = 15;

int i;

int middleRect_x1 = 0;
int middleRect_x2 = WINDOW_WIDTH;
float middleRect_y1 = (WINDOW_HEIGHT / 2) - 40;
float middleRect_y2 = (WINDOW_HEIGHT / 2) + 40;

float minJumpThing = (WINDOW_HEIGHT - middleRect_y2) / 2;

int playerScore = 0;
int playerLives = 0;

//function prototypes

void initRunner(Runner &runner);
void minimumGravRunner(Runner &runner);
void drawRunner(Runner &runner);
void runnerJump(Runner &runner);
void runnerFall(Runner &runner);
void stopRunner(Runner &runner);

void initShip(Ship &ship);
void drawShip(Ship &ship);
void moveShipUp(Ship &ship);
void moveShipDown(Ship &ship);
void stopShipBrick(Ship &ship);
void stopShipWindow(Ship &ship);

void initBullet(Bullet bullet[], int bulletSize);
void drawBullet(Bullet bullet[], int bulletSize);
void fireBullet(Bullet bullet[], int bulletSize, Ship &ship);
void updateBullet(Bullet bullet[], int bulletSize);

void initEnemy(Enemy &enemy, int enemySize);
void drawEnemy(Enemy &enemy);
void updateEnemy(Bullet bullet[], int enemySize, Enemy &enemy);

int main(void)
{
    //primitive variable
    bool done = false;
    bool redraw = true;

    float gameTime = 0;
    int frames = 0;
    int gameFPS = 0;

    Ship ship;
    Runner runner;
    Bullet bullet[5];
    Enemy enemy;

    //object variables

    //Allegro variables
    ALLEGRO_DISPLAY *display = NULL;
    ALLEGRO_EVENT_QUEUE *event_queue = NULL;
    ALLEGRO_TIMER *timer = NULL;
    ALLEGRO_FONT *arial = NULL;
    ALLEGRO_FONT *dosapp = NULL;

    //Initialization Functions
    if(!al_init())                                      //initialize Allegro
        return -1;

    display = al_create_display(WINDOW_WIDTH, WINDOW_HEIGHT);           //create our display object

    if(!display)                                        //test display object
        return -1;

    al_init_primitives_addon();
    al_install_keyboard();
    al_init_font_addon();
    al_init_ttf_addon();
    al_init_image_addon();

    event_queue = al_create_event_queue();
    timer = al_create_timer(1.0 / 60);

    arial = al_load_font("arial.ttf", 18, 0);
    dosapp = al_load_font("dosapp.fon", 40, 0);

    initBullet(bullet,NUM_BULLET);
    initRunner(runner);
    initShip(ship);
    initEnemy(enemy, NUM_ENEMY);

    al_register_event_source(event_queue, al_get_keyboard_event_source());
    al_register_event_source(event_queue, al_get_timer_event_source(timer));
    al_register_event_source(event_queue, al_get_display_event_source(display));

    al_start_timer(timer);
    gameTime = al_current_time();
    while(!done)
    {
        ALLEGRO_EVENT ev;
        al_wait_for_event(event_queue, &ev);

        if(ev.type == ALLEGRO_EVENT_TIMER)
        {
            if(keys[UP])
            {
                runnerJump(runner);
            }
            if(runner.y1 <= middleRect_y2 - 10)
            {
                runnerFall(runner);
                keys[UP] = false;
            }
            if(!keys[UP])
            {
                if(runner.y1 < (WINDOW_HEIGHT - 40))
                    runnerFall(runner);
                else if(runner.y1 >= runner.minimumJump - 40 && runner.y2 >= runner.minimumJump &&
                    runner.y1 != (WINDOW_HEIGHT - 40) && runner.y2
                    != WINDOW_HEIGHT)
                {
                    keys[UP] = true;
                    runnerJump(runner);
                }
            }
            if(keys[W])
                moveShipUp(ship);
            if(keys[S])
                moveShipDown(ship);
            if(ship.y1 <= 0)
                stopShipWindow(ship);
            else if(ship.y2 >= middleRect_y1)
                stopShipBrick(ship);
            if(keys[SPACE])
                drawBullet(bullet,NUM_BULLET);

            updateBullet(bullet,NUM_BULLET);
            updateEnemy(bullet,NUM_ENEMY,enemy);
        }
        else if(ev.type == ALLEGRO_EVENT_DISPLAY_CLOSE)
        {
            done = true;
        }
        else if(ev.type == ALLEGRO_EVENT_KEY_DOWN)
        {
            switch(ev.keyboard.keycode)
            {
                case ALLEGRO_KEY_ESCAPE:
                    done = true;
                    break;
                case ALLEGRO_KEY_UP:
                    if(runner.y1 == (WINDOW_HEIGHT - 40) && runner.y2 == WINDOW_HEIGHT)
                        keys[UP] = true;
                    break;
                case ALLEGRO_KEY_DOWN:
                    keys[DOWN] = true;
                    break;
                case ALLEGRO_KEY_W:
                    keys[W] = true;
                    break;
                case ALLEGRO_KEY_S:
                    keys[S] = true;
                    break;
                case ALLEGRO_KEY_SPACE:
                    if(!bullet[i].live)
                    {
                        keys[SPACE] = true;
                        fireBullet(bullet, NUM_BULLET, ship);
                    }
                    break;
            }
        }
        else if(ev.type == ALLEGRO_EVENT_KEY_UP)
        {
            switch(ev.keyboard.keycode)
            {
                case ALLEGRO_KEY_ESCAPE:
                    done = true;
                    break;
                case ALLEGRO_KEY_UP:
                    //if(runner.y1 <= runner.minimumJump - 40 && runner.y2 <= runner.minimumJump)
                        keys[UP] = false;
                    break;
                case ALLEGRO_KEY_DOWN:
                    keys[DOWN] = false;
                    break;
                case ALLEGRO_KEY_W:
                    keys[W] = false;
                    break;
                case ALLEGRO_KEY_S:
                    keys[S] = false;
                    break;
                case ALLEGRO_KEY_SPACE:
                    keys[SPACE] = false;
                    break;
            }
        }
        if(redraw && al_is_event_queue_empty(event_queue))
        {
            al_draw_filled_rectangle(middleRect_x1, middleRect_y1, middleRect_x2, middleRect_y2, al_map_rgb(255,255,255));
            al_draw_textf(arial,al_map_rgb(0,0,0),WINDOW_WIDTH / 2, (WINDOW_HEIGHT / 2) - 20,ALLEGRO_ALIGN_CENTRE,"Score: %d",
                playerScore);
            al_draw_textf(arial,al_map_rgb(0,0,0),WINDOW_WIDTH / 2, (WINDOW_HEIGHT / 2) + 13,ALLEGRO_ALIGN_CENTRE,"Lives: %d",
                playerLives);
            drawShip(ship);
            drawRunner(runner);
            drawBullet(bullet,NUM_BULLET);
            if(enemy.live = true)
                drawEnemy(enemy);

            al_flip_display();
            al_clear_to_color(al_map_rgb(0,0,0));
        }
    }
    al_destroy_event_queue(event_queue);
    al_destroy_timer(timer);
    al_destroy_font(arial);
    al_destroy_font(dosapp);
    al_destroy_display(display);                        //destroy our display object

    return 0;
}

void initRunner(Runner &runner)
{
    runner.ID = RUNNER;
    runner.x1 = 10;
    runner.x2 = runner.x1 + 40;
    runner.y1 = WINDOW_HEIGHT - 40;
    runner.y2 = runner.y1 + 40;
    runner.minimumJump = (middleRect_y2 + minJumpThing) + 45;
}
void drawRunner(Runner &runner)
{
    al_draw_filled_rectangle(runner.x1,runner.y1,runner.x2,runner.y2, al_map_rgb(255,255,255));
}
void runnerJump(Runner &runner)
{
    runner.y1 -= runnervy;
    runner.y2 -= runnervy;
}
void runnerFall(Runner &runner)
{
    runner.y1 += runnervy;
    runner.y2 += runnervy;
}
void stopRunner(Runner &runner)
{
    runner.y1 = (WINDOW_HEIGHT - 40);
    runner.y2 = WINDOW_HEIGHT;
}
void initShip(Ship &ship)
{
    ship.ID = SHIP;
    ship.x1 = 10;
    ship.x2 = ship.x1;
    ship.x3 = ship.x1 + 40;
    ship.y1 = (WINDOW_HEIGHT / 2) / 4 + 50;
    ship.y2 = ship.y1 + 40;
    ship.y3 = ship.y1 + 20;
}
void drawShip(Ship &ship)
{
    al_draw_filled_triangle(ship.x1,ship.y1,ship.x2,ship.y2,ship.x3,ship.y3,al_map_rgb(255,255,255));
}
void moveShipUp(Ship &ship)
{
    ship.y1 -= shipvy;
    ship.y2 -= shipvy;
    ship.y3 -= shipvy;
}
void moveShipDown(Ship &ship)
{
    ship.y1 += shipvy;
    ship.y2 += shipvy;
    ship.y3 += shipvy;
}
void stopShipWindow(Ship &ship)
{
    ship.y1 = 0;
    ship.y2 = 40;
    ship.y3 = 20;
}
void stopShipBrick(Ship &ship)
{
    ship.y1 = middleRect_y1 - 40;
    ship.y2 = middleRect_y1;
    ship.y3 = middleRect_y1 - 20;
}
void initBullet(Bullet bullet[], int bulletSize)
{
    for(int i = 0; i < bulletSize; i++)
    {
        bullet[i].ID = BULLET;
        bullet[i].speed = 20;
        bullet[i].live = false;
        keys[SPACE] = false;
    }
}
void drawBullet(Bullet bullet[], int bulletSize)
{
    for(int i = 0; i < bulletSize; i++)
    {
        if(bullet[i].live)
        {
            al_draw_filled_circle(bullet[i].x,bullet[i].y,2,al_map_rgb(255,255,255));
            keys[SPACE] = false;
        }
    }
}
void fireBullet(Bullet bullet[], int bulletSize, Ship &ship)
{
    for(int i = 0; i < bulletSize; i++)
    {
        if(!bullet[i].live)
        {
            bullet[i].x = ship.x3;
            bullet[i].y = ship.y3;
            bullet[i].live = true;
            keys[SPACE] = false;
            break;
        }
    }
}
void updateBullet(Bullet bullet[], int bulletSize)
{
    for(int i = 0; i < bulletSize; i++)
    {
        if(bullet[i].live)
        {
            bullet[i].x += bullet[i].speed;
            if(bullet[i].x >= WINDOW_WIDTH)
                bullet[i].live = false;
        }
    }
}
void initEnemy(Enemy enemy, int enemySize)
{
    for(int i = 0; i < enemySize; i++)
    {
        std::default_random_engine y1_generator;
        std::uniform_int_distribution<int> y1_distribution(0,middleRect_y1);
        enemy.ID = ENEMY;
        enemy.live = true;
        enemy.x1 = WINDOW_WIDTH + 50;
        enemy.x2 = enemy.x1 + 40;
        enemy.y1 = y1_distribution(y1_generator);
        enemy.y2 = enemy.y1 + 40;
        enemy.speed = 20;
    }
}
void drawEnemy(Enemy enemy)
{
    al_draw_filled_rectangle(enemy.x1,enemy.y1,enemy.x2,enemy.y2,al_map_rgb(255,0,0));
}
void updateEnemy(Bullet bullet[], int enemySize, Enemy enemy)
{
    for(int i = 0; i < enemySize; i++)
    {
        if(enemy.live)
        {
            std::default_random_engine y1_generator;
            std::uniform_int_distribution<int> y1_distribution(0,middleRect_y1);
            enemy.x1 = WINDOW_WIDTH + 50;
            enemy.x2 = enemy.x1 + 40;
            enemy.y1 = y1_distribution(y1_generator);
            enemy.y2 = enemy.y1 + 40;
            enemy.x1 -= enemy.speed;
            enemy.x2 -= enemy.speed;
            if(bullet[i].x == enemy.x1 && bullet[i].x == enemy.x2 - 40 && bullet[i].y >= enemy.y1 && bullet[i].y <= enemy.y2)
                enemy.live = false;
        }
    }
}

Answer 1

发生这种情况是因为，正如@DCoder 所说，您使用与您的定义略有不同的签名来转发声明函数。这导致编译器假定它们是两个不同的函数，因此出现错误。

修改下面的定义来修复它。 (基本上将所有 & 符号添加到您错过的 Enemy 变量中)

void initEnemy(Enemy& enemy, int enemySize)  
{


void drawEnemy(Enemy& enemy)
{

void updateEnemy(Bullet bullet[], int enemySize, Enemy& enemy)
{