USER-DEFINED METHODS - Java Programming: From Problem Analysis to Program Design - page 412

{ //Line 4

int number = 6; //Line 5

System.out.println("Line 6: Before calling"
+ "the method "
+ "primFormalParam, "
+ "number = " + number); //Line 6

primFormalParam(number); //Line 7

System.out.println("Line 8: After calling "
+ "the method "
+ "primFormalParam, "
+ "number = " + number);

//Line 8

} //end main //Line 9

public static void primFormalParam( int num) //Line 10

{ //Line 11

System.out.println("Line 12: In the method "
+ "primFormalParam, "
+ "before changing, num = "
+ num); //Line 12

num = 15; //Line 13

System.out.println("Line 14: In the method "
+ "primFormalParam, "
+ "after changing, num = "
+ num); //Line 14

} //end primFormalParam //Line 15

} //Line 16

Sample Run:
Line 6: Before calling the method primFormalParam, number = 6
Line 12: In the method primFormalParam, before changing, num = 6
Line 14: In the method primFormalParam, after changing, num = 15
Line 8: After calling the method primFormalParam, number = 6

The preceding program works as follows. The execution begins at the method main . The
statement in Line 5 declares and initializes the int variable number (see Figure 7-3).

main

number 6

FIGURE 7-3 The method main and its variable number

The statement in Line 6 outputs the value of number before calling the method
primFormalParam . The statement in Line 7 calls the method primFormalParam . The