Using Primitive Data Type Variables as Parameters

Submitted by GeePee on Monday, May 18, 2015 - 21:55.

The following java program application is about Primitive Data Type Variables as Parameters. When a method is called, the value of the actual parameter is copied into the corresponding formal Parameter. If a formal parameter is a variable of a primitive data type, then after copying the value of the actual parameter, there is no connection between the formal parameter and the actual parameter. I will be using the JCreator IDE in developing the program. To start in this tutorial, first open the JCreator IDE, click new and paste the following code.

public class PrimitiveType
{
        public static void main (String[] args)
        {
                int number = 6;
                
                System.out.println("before calling "
                        + "the method funcPrimFormalParam number = " + number);
                                
                        funcPrimFormalParam(number);
                        
                        System.out.println("after calling"
                                + "the method funcPrimFormalParam number = " + number);
        }
        public static void funcPrimFormalParam(int num)
        {
                System.out.println("In the method funcPrimFormalParam, before "
                        + "changing, num = " + num);
                        
                        num = 15;
                        
                        System.out.println("the mehod funcPrimFormalParam, after changing, num = " + num);
                
        
        }
}

Sample Run:


Before calling the method funcPrimFormalParam, number = 6
In the method funcPrimFormalParam, before changing, num = 6
In the method funcPrimFormalParam, after changing, num = 15
After calling the method funcPrimFormalParam, number = 6

The preceding program works as follows: The execution begins at the method main. The segment int number = 6;declares and initializes the int variable number. The statement

System.out.println("before calling "
                        + "the method funcPrimFormalParam number = " + number);

outputs the value number before calling the method funcPrimFormalParam. The statement funcPrimFormalParam(number);calls the method funcPrimFormalParam. The value of the variable number is passed to the formal parameter num. The statement

System.out.println("In the method funcPrimFormalParam, before "
                        + "changing, num = " + num);

outputs the value of num before changing its value. The statement num = 15; changes the value of num to 15. The statement System.out.println("the mehod funcPrimFormalParam, after changing, num = " + num);outputs the value of num. After this statement executes, the method funcPrimFormalParam exits and control goes back to the method main. The statement

 System.out.println("after calling"
                                + "the method funcPrimFormalParam number = " + number);

outputs the value of number after calling the method funcPrimFormalParam.

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