[Solved] I can’t get the sum of the list [closed]

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Let’s do it in parts

  • Generate random numbers. You are generating from a = 1 to a = 49 random numbers insted of 50. If you know how many times you want to iterate, you may use the for loop.

  • Math.random() returns a double, so you have to cast to int with (int) before it. See documentation here

  • In calculateTotal() you are iterating over numbers but you are not adding to total, so the value of total would be the last element of numbers. Also you have to initialize the variable total to 0, otherwise you will get an error.

  • I add an extra function to calculate the total with lambda and streams included in Java 8. The Integer::intValue calls the method by reference.

public class MyClass {

    public static ArrayList<Integer> numbers = new ArrayList<Integer>();

    public static void main(String[] args) {
        // Generate 50 different prices
        for (int i = 0; i < 50; i++) {
            int num = (int) (Math.random() * 100 + 1); // Add casting
            numbers.add(num);
        }

        System.out.println(calculateTotal());
        System.out.println(calculateTotalJava8());
    }

    public static int calculateTotal() {
        int total = 0; // Initialize to 0
        for (Integer price : numbers) {
            total += price; // Add the price to the total
        }
        return total;
    }
    
    public static int calculateTotalJava8() {
        int total = numbers.stream().mapToInt(Integer::intValue).sum();
        return total;
    }
}

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solved I can’t get the sum of the list [closed]