Segmentation fault in vector

[ben353]

Ok so I've made a little game using SDL but when I try to 'destroy enemies' in a radius of my character I try to remove the x and y coordinates of the 'enemies' from their respective vectors. When I run it the 'enemies' are removed/it works but the program then closes and the terminal returns 'Segmentation Fault'. Why is this?

void ship_fire() {
	if (bombs_away){						//If spacebar is pressed
		int proximity;
		for (int j=0; j<n_enemy; j++) {
			proximity = sqrt(pow(x_enemy[j]-a,2.0) + pow(y_enemy[j]-b,2.0));		
			if (proximity <=50) {
				x_enemy[j] = x_enemy.back();
				x_enemy.pop_back();

				y_enemy[j] = y_enemy.back();
				y_enemy.pop_back();
			}
		}
	}
}

[ben353]

It's ok figured it out! I had to return the bool to false after the 'if' statement