如何使用 arrays 创建方法？

Question

How do you create a method that accepts a one-dimensional array and a string as its arguments?

• Use a linear search to identify if the product is in the array. If the name is in the array, the method should return the position. If the number is not in the array, the method should return-1.

• When the user enters the name of a product, the program should step through the ArrayList.

public static void main(String[] args) {

    ArrayList<String> products = new ArrayList<>();

    products.add("Pencil pouch");
    products.add("pen");
    products.add("Pencil sharpener");
    products.add("High lighters");
    products.add("Markers");
    products.add("Erasers");
    products.add("Binder");
    products.add("Notebooks");
    products.add("Index cards");
    products.add("Folders");
    products.add("Glue");
    products.add("Ruler");
    products.add("Scissors");
    products.add("Calculator");
    products.add("Calendar");
    products.add("Backpack");

    for (String i: products) {
        System.out.println(i);
    }
}

public static int searchProducts(int[] products) {
    System.out.println("enter all names of product");

    Scanner input = new Scanner(System.in);
    String x = input.nextLine();

    for (i = 0; i < products.length; i++){
        if (products][i] == x)
        return i;

    }

    return -1;
}

Answer 1

Ok, you're using an ArrayList. To accept multiple parameters, take a look at this link: https://www.w3schools.com/java/java_methods_param.asp

Regarding your method, you should accept 2 parameters, not 1. In addition, you should accept an ArrayList, not a 1D array, and it should be of type String, not int. Your method should look something like this:

public int searchProducts(ArrayList<String> arr, String str) {
    // you don't need to create a scanner object because the string you 
    intend to use is a parameter of the method
    
    for(int i=0; i<arr.size(); i++) {
        if(arr.get(i).equals(str)) {
            return i;
        }
    }
    return -1;
    
}

So now, if you want to call the method in your main(), you have to pass in your products ArrayList and the item you desire to find.