자동 포장 함정
1883 단어 자동 포장 함정
public class test{
public static void main(String [] args){
Integer a = 1;
Integer b = 2;
Integer c = 3;
Integer d = 3;
Integer e = 321;
Integer f = 321;
Long g = 3L; // //
System.out.println(c == d);//true true
// “==” ,
//
System.out.println(e == f);//false false
// “==” ,
System.out.println(c == (a+b));//false true
System.out.println(c.equals(a+b));//true true
System.out.println(g == (a+b));//false true
// equals
// g a+b ,
System.out.println(g.equals(a+b));//true false
}
}
class :
public class test
{
public test()
{
}
public static void main(String args[])
{
Integer a = Integer.valueOf(1);
Integer b = Integer.valueOf(2);
Integer c = Integer.valueOf(3);
Integer d = Integer.valueOf(3);
Integer e = Integer.valueOf(321);
Integer f = Integer.valueOf(321);
Long g = Long.valueOf(3L);
System.out.println(c == d);
System.out.println(e == f);
System.out.println(c.intValue() == a.intValue() + b.intValue());
System.out.println(c.equals(Integer.valueOf(a.intValue() + b.intValue())));
System.out.println(g.longValue() == (long)(a.intValue() + b.intValue()));
System.out.println(g.equals(Integer.valueOf(a.intValue() + b.intValue())));
}
}