Method call error manufacturingcontroller

I don’t understand what the mistake is. Task:

You are given two methods, requestProduct and getNumberOfProducts:

getNumberOfProducts should return the total number of requested products; requestProduct should keep track of requested products, and format the product argument in the format: No. Requested Detail.

For example:

ManufacturingController.requestProduct(“detail 1”); should return:

1. Requested detail 1

and

ManufacturingController.requestProduct(“Wrench”); should return:

2. Requested Wrench

After execution of these two commands,

ManufacturingController.getNumberOfProducts(); should return:

2

public class DetailManufacturing {
    public static void main(String[] args) {
        System.out.println(requestProduct("Wrench"));
        System.out.println(getNumberOfProducts());
    }

    public static String requestProduct(String product) {
        // write your code here
        return getNumberOfProducts() + ". Requested " + product;
    }

    public static int getNumberOfProducts() {
          // write your code here
        int count=0;
            count++;
        return count;
    }
}

Answer

What you need is a variable that will keep the count of how many times request has been made.
One way to do this is using static variable.

public class DetailManufacturing {
    static count = 0; // This will get memory only once and shared with others while retaining it's value.

    public static void main(String[] args) {
        ...
    }

    public static String requestProduct(String product) {
        count++; // each time request is made, increment it's value
        return getNumberOfProducts() + ". Requested " + product;
    }

    public static int getNumberOfProducts() {
        return count;
    }

}