What's wrong with "this" pointer? - c++

Question

So, i decided to create a collision detection function in my game and i put it into the class of enemies. Then i put it to "enemy.cpp" and i used "this" pointer.
The code:
if(((this->sprite.getPosition().y + this->sprite.getTextureRect().height) >= blocklist[i].sprite.getPosition().y) &&
(this->sprite.getPosition().y <= blocklist[i].sprite.getPosition().y))
This gives me SIGSEGV segmentation error. I can't find what could be the problem in this line, here is the enemyclass for reference.
class enemyclass
{
public:
sf::Sprite sprite;
sf::Sprite bubble;
//PROPERTIES
float xspeed, yspeed;
int x, y;
float health;
bool colR, colL, colU, colD;
int skin;
void detectCollisions(int blocksize);
};
and the blockclass that i made a vector of to use as a list of enemies:
class blockclass
{
public:
sf::Sprite sprite;
int x, y;
};
I would be very thankfull for an answer since i can't find out what's wrong.

Answer 1

As others have said, if some complicated instruction causes an error, split it into smaller parts and see, in which part the error arises:
if( this->x == 0) // changes nothing
x = 0; // but validates 'this'
int thisy = sprite.getPosition().y;
int thish = sprite.getTextureRect().height;
sf::Sprite &that = blocklist[i].sprite;
if( that.x == 0) // validate 'that'
that.x = 0;
int thaty = that.getPosition().y;
if(thisy + thish >= thaty && thisy <= thaty) {
// ......
}