在下面程序中，各个表达式里使用了哪些转换？ struct X

struct X { 
  int I;
  X(int);
  X operator+(int);
};
struct Y { 
  int X;
  Y(X);
  Y operator+(X);
  operator int();
};
extern X operator*(X, Y);
extern int f(X);
X x = 1;
Y y = x;
int i = 2;
int main() {
  i+10; y+10; y+10*y;
  x+y+i; x*x+i; f(7);
  f(y); y+y; 106+y;
};