I'm currently working on my first space shooter, and I'm in the process of making my ship shoot some bullets/lasers. Unfortunately, I'm having a hard time getting the bullets to fly vertically. I'm a total noob when it comes to this so you might have a hard time understanding my code :/

    // Position Bullet Function
    projectilex = x + 17;
    projectiley = y + -20;
    if(keystates[SDLK_SPACE])
    {
        alive = true;
    }

And here's my show function

    if(alive)
    {

        if(frame == 2)
        {
            frame = 0;
        }
        apply_surface(projectilex,projectiley,ShootStuff,screen,&lazers[frame]);
        frame++;
        projectiley + 1;
    }

I'm trying to get the bullet to fly vertically... and I have no clue how to do that. I've tried messing with the y coordinate but that makes things worse. The laser/bullet just follows the ship :(

How would I get it to fire at the starting position and keep going in a vertical line without it following the ship?

int main( int argc, char* args[] )
{
Player p;
Timer fps;
bool quit = false;
if( init() == false )
{
    return 1;
}

//Load the files
if( load_files() == false )
{
    return 1;
}

clip[ 0 ].x = 0;
clip[ 0 ].y = 0;
clip[ 0 ].w = 30;
clip[ 0 ].h = 36;

clip[ 1 ].x = 31;
clip[ 1 ].y = 0;
clip[ 1 ].w = 39;
clip[ 1 ].h = 36;

clip[ 2 ].x = 71;
clip[ 2 ].y = 0;
clip[ 2 ].w = 29;
clip[ 2 ].h = 36;

lazers [ 0 ].x = 0;
lazers [ 0 ].y = 0;
lazers [ 0 ].w = 3;
lazers [ 0 ].h = 9;

    lazers [ 1 ].x = 5;
lazers [ 1 ].y = 0;
lazers [ 1 ].w = 3;
lazers [ 1 ].h = 7;


while( quit == false )
{
    fps.start();
    //While there's an event to handle
    while( SDL_PollEvent( &event ) )
    {
        p.handle_input();
        //If a key was pressed


        //If the user has Xed out the window
        if( event.type == SDL_QUIT )
        {
            //Quit the program
    quit = true;
    }

    }

    //Scroll background
    bgX -= 8;

    //If the background has gone too far
    if( bgX <= -GameBackground->w )
    {
    //Reset the offset
    bgX = 0;
    }
    p.move();
    apply_surface( bgX, bgY,GameBackground, screen );
    apply_surface( bgX + GameBackground->w, bgY, GameBackground, screen );

    apply_surface(0,0, FullHealthBar,screen);

    p.shoot();
    p.show();
    //Apply the message
    //Update the screen
    if( SDL_Flip( screen ) == -1 )
    {
    return 1;
    }
    SDL_Flip(GameBackground);
    if( fps.get_ticks() < 1000 / FRAMES_PER_SECOND )
    {
    SDL_Delay( ( 1000 / FRAMES_PER_SECOND ) - fps.get_ticks() );
    }
    }
    //Clean up
    clean_up();
    return 0;
    }