'How do i multiply two one-dimensional arrays?

I will be honest with you, I have absolutely no idea what i am doing, nor have the slightest of ideas where to look and it is my homework so if someone would be kind enough to help me out, I would be truly grateful.

"Write a program that declares three arrays named price, qty, and amt. Each array should be declared in main()and capable of holding 3 values. Make up numbers for price and qty (quantity).(ShoppingCart.java) (4 pts) Write a method to fill the amt array with the product of the corresponding elements in price and qty. (3–create a method within the ShoppingCart class)"

What i have attempted is just this:

public class Shoppingjava {

    public static void main(String[] args) {

        int price[] = {4, 9, 7};
        int qty[] = {2, 5, 3};
        int amt[] = new int[3];

        System.out.println(product(price, qty));
    }

    public product(int P[], int Q[]) {
        int[][] c = new int[P.length][Q.length];
        return product;
    }

}

But i really don't know where to go with this, I am sorry to bother anyone with this and if it someone is willing to help me out, thank you.

javaarrays


Solution 1:[1]

Array elements can be accessed by their index in the form int val = arr[0] (for retrieving) or arr[i] = val (for storing).

You can iterate through the parallel arrays price and qty with a for loop, cycling through each index, and storing the product of each pair in amt.

Generic code:

for (int i = 0; i < arrZ.length; i++) {
    arrZ[i] = arrX[i] * arrY[i];
}

Your scenario:

for (int i = 0; i < amt.length; i++) {
    amt[i] = price[i] * qty[i];
}

I'd also recommend referring to the Java tutorials for using arrays: https://docs.oracle.com/javase/tutorial/java/nutsandbolts/arrays.html

Solution 2:[2]

public class ShoppingCart {
    public static void main(String[] args) {

        int price[] = {4, 9, 7};
        int qty[] = {2, 5, 3};
        int amt[] = new int[3];

        for (int i = 0; i < price.length; i++) {
            amt[i] = price[i] * qty[i];
            System.out.println(amt[i]);    //TESTING
        }
    }

Solution 3:[3]

public class ShoppingCart {

    public static void main(String[] args) {

        int price[] = {4, 9, 7};
        int qty[] = {2, 5, 3};
        int amt[] = new int[3];

        //calculate amounts
        product(price, qty, amt);
    
        //prints details
        System.out.println("Price  Quantity  Amount");
        for (int i = 0; i < price.length; i++) {
            System.out.println(price[i]+"      "+qty[i]+"         "+amt[i]);
        }
    
    }

    public static void product(int price[], int quantity[], int amount[]) {
        for (int i = 0; i < price.length; i++) {
            amount[i] = price[i] * quantity[i];
        }
    }
}

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2 always007
Solution 3 Dinushika Rathnayake

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