Question

given the following code which instance variables and methods are at the class level or which ones are not instance variables or methods ?

class employee
{
static int count = 0;
string id;
double hours;
double wages;

public employee(string arg_id, double arg_hours, double arg_wage)
{

}

public static int getcount()
{
return count;
}

public double calcpay()
{
return 0.0;
}

public static void main(string args)
{

}
}

a)
main method, getcount method, count variable

b)
employee constructor method, main method, count variable

c)
main method, id variable, count variable, getcount method

d)
getcount method, count variable, id variable, calcpay method

Explanation:

🆕 New Concept Discovered: Static vs. Instance Members
Variables and methods marked static belong to the class itself, not to individual objects.

Step 1: Identify Class-Level (Static) Members

In Java, members declared with the static keyword belong to the class level rather than to any specific instance of the class. Looking at the provided code:

• static int count = 0; is a class-level variable because of the static keyword.
• public static int getCount() is a class-level method because of the static keyword.
• public static void main(String args[]) is a class-level method because of the static keyword.

These three elements are NOT instance variables or methods; they are class-level (static) members.

Step 2: Identify Instance-Level Members

Members that do not have the static keyword belong to individual instances (objects) of the class:

• id, hours, and wages are instance variables.
• The Employee constructor is used to initialize instances.
• calcPay() is an instance method.

Step 3: Match with the Options

We are looking for the option that lists the members that are at the class level (i.e., NOT instance variables or methods):

• a) main method, getCount method, count variable (All of these are declared static, meaning they are class-level).
• b) Employee constructor method, main method, count variable (The constructor is not a static class-level method).
• c) main method, id variable, count variable, getCount method (id is an instance variable).
• d) getCount method, count variable, id variable, calcPay method (id and calcPay are instance-level).

Therefore, option a is the correct choice.

Answer:

a