long double slope(int i,int j) {
	return (long double)(y(j)-y(i))/(x(j)-x(i));
}

long double slope(int i,int j) {
	return (long double)(y(i)-y(j))/(x(i)-x(j));
}

请问各位大神，这样两个代码的区别是什么?
拜托拜托!!!