问题:交换a和b的值。class NewClass {
public static void main(String[] args) {
Integer a, b;
a=3; b=4;
swap(a, b);
System.out.println("a=" + a + " b=" + b);
} public static void swap(Integer a, Integer b) {
/*
* ???
*/
}
}
public static void main(String[] args) {
Integer a, b;
a=3; b=4;
swap(a, b);
System.out.println("a=" + a + " b=" + b);
} public static void swap(Integer a, Integer b) {
/*
* ???
*/
}
}
public static void main(String[] args) { myInt a = new myInt(10);
myInt b = new myInt(20);
swap(a, b);
System.out.println("a:" + a + " b:" + b);
} public static void swap(myInt a, myInt b) {
int temp = a.getInt();
a.setInt(b.getInt());
b.setInt(temp);
}
}class myInt {
int a; myInt(int a) {
this.a = a;
} public int getInt() {
return a;
} public void setInt(int b) {
a = b;
} myInt(myInt a) {
this.a = a.getInt();
} public String toString() {
return "" + a;
}
}
为什么要自己实现一个Int包装类呢,直接传个int型的不就行了吗?