A l'aide, comment extraire la partie entière

public static void f(double d)
{
    System.out.println("double= "+d
        +", round= "+Math.round(d)
        +", rint= " +Math.rint(d)
        +", floor= "+Math.floor(d)
        +", ceil= " +Math.ceil(d));
}

public static void main(String[] args) 
{
    f(1.2); // round=  1, rint=  1.0, floor=  1.0, ceil=  2.0
    f(1.8); // round=  2, rint=  2.0, floor=  1.0, ceil=  2.0
    f(-1.2);// round= -1, rint= -1.0, floor= -2.0, ceil= -1.0
    f(-1.8);// round= -2, rint= -2.0, floor= -2.0, ceil= -1.0
}