Java中第一个和最后一个数组元素的总和

Question

I'm using JB IntelliJ IDEA and trying to create a program which finds the sum of the first and last elements of a randomly generated array using the sum() method. My problem is that an error occures, please help me.

Here is my code:

package com.company;
import java.util.Random;
public class Main {
    public static int sum(int[] array) {
        int x = array[0];
        int y = array[9];
        int z = x + y;
        return z;
    }
    public static void main(String[] args) {
        int[] array = new int[10];
        Random rand = new Random();
        for (int i = 0; i < array.length; i++) {
            int j = rand.nextInt(50);
            System.out.println(sum());
        }
    }
}

and error:

Error:(15, 32) java: method sum in class com.company.Main cannot be applied to given types;
required: int[]
found: no arguments
reason: actual and formal argument lists differ in length

Answer 1

** Error:(15, 32) java: method sum in class com.company.Main cannot be applied to given types;

required: int[]

found: no arguments

reason: actual and formal argument lists differ in length

Going through the Error itself says everything about the issue:

required: int[]

found: no arguments

It is saying that it required an array of data type int which is missing(no arguments) and that is why actual and formal argument lists differ in length

Hence, Sum function requires an array to be passed as a parameter.

Also, you are getting random integer value in a integer variable j = rand.nextInt(50); but not assigning it to the array which is just wasting the loop to run unnecessarily 10 times.

Instead of assigning it to j we can directly assign it to the array and fill array with the random integers before passing it to the method sum(array) :

Try this updated code with the changes needed:

package com.company;
import java.util.Random;
public class Main {
    public static int sum(int[] array) {
        int x = array[0];
        int y = array[9];
        int z = x + y;
        return z;
    }
    public static void main(String[] args) {
        int[] array = new int[10];
        Random rand = new Random();
        for (int i = 0; i < array.length; i++) {
            array[i] = rand.nextInt(50);
        }
        System.out.println(sum(array));
    }
}

Answer 2

You did not pass the array to the method. Change your line

System.out.println(sum());

to

System.out.println(sum(array));

Also you did not put j into array and you call sum before array is filled.

Answer 3

You method sum requires an attribute of the type int[]. But in the statement System.out.println(sum()); you are not passing an attribute to your method.

Try out this code:

    public static int sum(int[] array) {
        int x = array[0];
        int y = array[9];
        int z = x + y;
        return z;
    }
    public static void main(String[] args) {
        int[] array = new int[10];
        Random rand = new Random();
        for (int i = 0; i < array.length; i++) {
            array[i] = rand.nextInt(50);
            System.out.println(array[i]);
        }
        System.out.println(sum(array));
    }

Answer 4

You should initialize the array with the random() , and then put the array as an argument to call sum() function. The codes as follows:

public static void main(String[] args) {
    int[] array = new int[10];
    Random rand = new Random();
    for (int i = 0; i < array.length; i++) {
        int j = rand.nextInt(50);
        array[i] = j;
    }
    System.out.println(sum(array));
}

And then, you can get the result that you want.