Java Reference
In-Depth Information
Note that the definition of the method setTime checks for the valid values of hours ,
minutes ,and seconds . If any of these values is out of range, the corresponding instance
variable is initialized to 0 . Now let's look at how the method setTime works.
The method setTime is a void method and has three parameters. Therefore:
￿ A call to this method is a stand-alone statement.
￿ We must use three parameters in a call to this method.
Furthermore, recall that because setTime is a member of the class Clock , it can directly
access the instance variables hr , min , and sec , as shown in the definition of setTime .
Suppose that the object myClock is as shown in Figure 8-7.
hr 12
min 36
sec 49
myClock
FIGURE 8-7 Object myClock
Consider the following statement:
myClock.setTime(3, 48, 52);
The variable myClock accesses the member setTime .Inthe tement
myClock.setTime(3, 48, 52); , setTime is accessed by the variable myClock . There-
fore, the three variables— hr , min , and sec —referred to in the body of the method
setTime are the three instance variables of the object myClock . Thus, the values 3 , 48 ,
and 52 , which are passed as parameters in the preceding statement, are assigned to the
three instance variables of the object myClock by the method setTime (see the body of
the method setTime ). After the previous statement executes, myClock is as shown in
Figure 8-8.
hr 3
min 48
myClock
sec 52
FIGURE 8-8 myClock after statement myClock.setTime(3,48,52); executes
 
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