calculateAreaRhombus()

Step 1: Understanding the problem

The first step is to understand the problem. A rhombus is a quadrilateral all of whose sides have the same length. The area of a rhombus can be calculated using the formula: Area = (p*q)/2 where p and q are diagonals of the rhombus. In this step, we define the problem and decide on the inputs and outputs of the function.

Input: Diagonals of the rhombus (double p, double q) Output: Area of the rhombus (double)

public double calculateAreaRhombus(double p, double q) {
    // ... code implementation ...
}

Step 2: Writing the function header

Next step is to write the function header. We define the function with the name calculateAreaRhombus, accept two double parameters (p and q), and returns a double value representing the area of the rhombus.

public double calculateAreaRhombus(double p, double q) {
    // ... code implementation ...
}

Step 3: Writing the function body

The third step involves writing the actual logic for calculating the area of the rhombus inside the function body. This includes multiplying the diagonals, dividing by 2.

public double calculateAreaRhombus(double p, double q) {
    return (p*q)/2;
}

Step 4: Testing the function

Now, we should test our function with some test cases to make sure it's working as expected.

public static void main(String[] args) {
    System.out.println(calculateAreaRhombus(10, 20));  // refers to a rhombus with diagonals 10 and 20 
}

Conclusion

The above simple function calculates the area of a rhombus given its diagonals. The function simply multiplies the two inputs and divides them by 2 to give the area of the rhombus. Always remember to test your function with various inputs to make sure it works correctly in all cases.