一段代码，两个神奇的BUG，啊！大佬救命

#include<stdio.h>
#include<windows.h>
#define WIDTH 80
#define HEIGHT 20
// 全局变量的定义
int position_x, position_y;
int enemy_x, enemy_y;
int mybullet_x, mybullet_y;
int myHP, enemyHP;
int isFire;
int score;
void gotoxy(int x, int y) // 定义，光标移动到(x, y)位置
{
HANDLE handle = GetStdHandle(STD_OUTPUT_HANDLE);
COORD pos;
pos.X = x;
pos.Y = y;
SetConsoleCursorPosition(handle, pos);
}
void HideCursor()
{
CONSOLE_CURSOR_INFO cursor_info={1, 0}; // 第二个值为0表示隐藏光标
SetConsoleCursorInfo(GetStdHandle(STD_OUTPUT_HANDLE), &cursor_info);
}
void startup()
{
position_x = WIDTH/4;
position_y = HEIGHT*3/4;
enemy_x = WIDTH*3/4;
enemy_y = HEIGHT*3/4;
mybullet_x = WIDTH+1;
myHP = 100;
enemyHP = 100;
score = 0;
}
void show()
{
gotoxy(0,0);
HideCursor();
int i, j;
for(j=0;j<HEIGHT;j++)
{
for(i=0;i<WIDTH;i++)
{
if(j==position_y && i==position_x)
printf("@");
else if(j==mybullet_y && i==mybullet_x)
printf("-");
else if(j==enemy_y && i==enemy_x)
printf("#");
else
printf(" ");
}
printf("\n");
}
printf("我的HP：%d\n", myHP);
printf("对手的HP：%d\n", enemyHP);
printf("得分：%d\n", score);
}
void updateWithoutInput()
{
int i, j;
if(mybullet_x==enemy_x && mybullet_y==enemy_y)
{
score++;
enemyHP-=25;
printf("enemyHP:%d\n",enemyHP);
}
if(mybullet_x<WIDTH)
mybullet_x++;
}
void updateWithInput()
{
if(kbhit())
{
char key = getch();
if(key==' ')
{
mybullet_x = position_x+1;
mybullet_y = position_y;
}
if(position_y==HEIGHT*3/4)
{
if(key=='a')
position_x--;
if(key=='d')
position_x++;
if(key=='w')
position_y--;
}
}
}
int main()
{
startup();
while(1)
{
show();
updateWithoutInput();
updateWithInput();
}
return 0;
}