1. The transmission parameter values, intended Guming Si, the value of a variable is passed to another variable.
such as:
int x = 10，y；
y = x；
Wherein the value of x y passed, the value of y is 10, but the value is still 10 x.
Which in the end is how to achieve it?
In fact, here by value (i.e., assigned) to the present value of x is not used, but its copy.
It will not affect the value of x. Y parameter value obtained is equivalent to life in the "original" "and" copy. "
Operation on the x-y will not be affected, this is the principle parameters of traditional values. Similarly, the reference value of the parameter type of pass It is also a copy to the address number.
2. The combination of object
First, we know that a class can own it as an object a member variable, if you create an object with such a class, then this object will have other objects, which means that this object will other subject as part of their own, which is Has-a.
If the object is a combination of the object b, then the object can be a delegate object b calls their method, the object is a multiplexing method in combination with the object b.
Other class methods we can cite this way.
example:
package shaman4_2;
public class Family {
TV homeTV;
void buyTV(TV tv)
{
homeTV = tv;
}
void remoteControl(int m)
{
homeTV.setChannel(m);
}
void seeTV()
{
homeTV.showProgram();
}
}
package shaman4_2;
public class TV {
int channel;
void setChannel(int m)
{
if(m>=1) {
channel = m;
}
}
int getChannel()
{
return channel;
}
void showProgram()
{
switch(channel)
{
case 1 : System.out.println("综合频道");
break;
case 2 : System.out.println("经济频道");
break;
case 3 : System.out.println("文艺频道");
break;
case 4 : System.out.println("国际频道");
break;
case 5 : System.out.println("体育频道");
break;
default : System.out.println("不能收看"+channel+"频道");
}
}
}
package shaman4_2;
public class MainClass {
public static void main(String[] args) {
TV haierTV = new TV();
haierTV.setChannel(5);
System.out.println("haierTV的频道是"+haierTV.getChannel());
Family zhangSanFamily = new Family();
zhangSanFamily.buyTV(haierTV);
System.out.println("zhangSanFamily开始看电视节目");
zhangSanFamily.seeTV();
int m = 2;
System.out.println("zhangSanFamily将电视更换到"+m+"频道");
zhangSanFamily.remoteControl(m);
System.out.println("haierTV的频道是"+haierTV.getChannel());
System.out.println("zhangSanFamily在看电视节目");
zhangSanFamily.seeTV();
}
}
This example illustrates the combination of a good object reuse
study summarized above includes personal, such as unreasonable exist, welcome to point out, learn from each other.
