SDL Increment counter on keystroke - c++

Question

So I'm learning SDL and I'm trying to make a basic menu. The menu consists of "Start", below it "Load" and below it "Quit". None of them have a function, they're just for show.
What I'm doing is adding a box that surrounds the selected option. I tried to make it so whenever up or down is pressed on the keyboard, the counter will be incremented or lowered by one and the box will move up or down. However, every time I press one of the buttons the counter goes to huge numbers. I know that because I wrote alongside code that displays the counter on the screen.
I would really appreciate any help with what I'm doing wrong.
screenshot: http://i.imgur.com/6Io8cLj.png
PS: I'm using a header file with a function apply_surface() so I'll add it first.
Start of head.h:
#ifndef CYOP_H_HEADER
#define CYOP_H_HEADER
#include "SDL/SDL.h"
#include "SDL/SDL_image.h"
#include "SDL/SDL_ttf.h"
using namespace std;
void apply_surface(int x, int y, SDL_Surface* source, SDL_Surface* destination)
{
SDL_Rect offset;
offset.x = x;
offset.y = y;
Uint32 colorkey = SDL_MapRGB( source->format, 0, 0xFF, 0xFF );
SDL_SetColorKey(source, SDL_SRCCOLORKEY, colorkey);
SDL_BlitSurface(source, NULL, destination, &offset);
}
#endif
Start of main.cpp:
#include "SDL/SDL.h"
#include "SDL/SDL_image.h"
#include "SDL/SDL_ttf.h"
#include "head.h"
#include <string>
#include <sstream>
using namespace std;
// Text rendering parts
TTF_Font *font = NULL;
SDL_Color color = {255, 0, 0};
int cur=0; // Current Menu Item (0 is start, 1 is Load, 2 is Quit)
string str = "Counter: ";
string num;
string strc = str+num;
bool quitp = false; //Quit Program bool
ostringstream convert;
SDL_Surface* background = NULL;
SDL_Surface* start = NULL;
SDL_Surface* load = NULL;
SDL_Surface* quit = NULL;
SDL_Surface* screen = NULL;
SDL_Surface* select = NULL;
SDL_Surface* message = NULL;
SDL_Event event;
void selected(int n)
/*Function that is supposed to reload all images again,
only the "select" picture at a different place**/
{
convert << cur;
num=convert.str();
strc=str+num;
message = TTF_RenderText_Solid(font, strc.c_str(), color); // Renders "Counter: *number
of cur **/
int arr[3]={50, 100, 150};
apply_surface(0,0,background,screen);
apply_surface(60,50,start,screen);
apply_surface(60,100,load,screen);
apply_surface(60,150,quit,screen);
apply_surface(0, 0, message, screen);
apply_surface(60, arr[n], select, screen);
SDL_Flip(screen);
}
int main(int argc, char* args[])
{
SDL_Init(SDL_INIT_EVERYTHING);
TTF_Init();
screen = SDL_SetVideoMode(300, 300, 32, SDL_SWSURFACE);
font = TTF_OpenFont("grasping.ttf", 28);
message = TTF_RenderText_Solid(font, strc.c_str(), color);
background = IMG_Load ("background.bmp");
start = IMG_Load ("start1.bmp");
load = IMG_Load ("load1.bmp");
quit = IMG_Load ("quit1.bmp");
select = IMG_Load ("select.bmp");
apply_surface(0,0,background,screen);
apply_surface(60,50,start,screen);
apply_surface(60,100,load,screen);
apply_surface(60,150,quit,screen);
apply_surface(60, 50, select, screen);
apply_surface(0, 0, message, screen);
SDL_Flip(screen);
while(quitp==false)
{
if(SDL_PollEvent(&event));
{
if (event.type == SDL_QUIT)
{
quitp = true;
}
if (event.type == SDL_KEYDOWN)
{
SDLKey keyPressed = event.key.keysym.sym;
switch (keyPressed)
{
case SDLK_DOWN:
cur++;
break;
case SDLK_UP:
cur--;
break;
default: break;
}selected(cur);
}// Closing if(event.type == SDL_KEYDOWN)
}// Closing if(SDL_PollEvent)
} // Closing main while loop
SDL_Quit();
return 0;
}

Answer 1

There are two problems:
The first is a classic rookie mistake:
if(SDL_PollEvent(&event));
What you meant to do here is this:
if(SDL_PollEvent(&event))
Amazing what a difference one character makes!
The second issue is this:
However, every time I press one of the buttons the counter goes to
huge numbers. I know that because I wrote alongside code that displays
the counter on the screen.
You need to look a little more closely at that screenshot. The number it's printing out is 123456789101112. See the pattern there?
cur = 1, strc = "Counter: 1"
cur = 2, strc = "Counter: 12"
cur = 3, strc = "Counter: 123"
cur = 4, strc = "Counter: 1234"
..etc
The way you're using the string stream just appends the number each time. The easy solutions here are to either not use the same string stream each time, or to reset it to the empty string.