Сложить все числа массива java

How to find sum of array elements in java

Sum of array elements means the sum of all the elements(or digits) in the array. Array elements can be integers( int ) or decimal numbers( float or double ).
There are different methods to calculate sum of elements in an array in java and this post discusses them all.

Method 1 : Using for loop
This is a traditional and most commonly used approach where the array is iterated using a for loop.
In each iteration, the current array element is added to a variable which holds the sum of array elements.
This variable is initialized to 0 before the start of loop. Example,

public class ArraySumCalculator { public static void main(String[] args) { int[] array = { 1, 34, 67, 23, -2, 18 }; // variable to hold sum of array elements int sum = 0; // iterate using a for loop for (int loopCounter = 0; loopCounter < array.length; loopCounter++) { // get current array element int element = array[loopCounter]; // add element to sum sum += element; } System.out.println("Sum of array elements is: " + sum); } }

public class ArraySumCalculator < public static void main(String[] args) < int[] array = < 1, 34, 67, 23, -2, 18 >; // variable to hold sum of array elements int sum = 0; // iterate using a for loop for (int loopCounter = 0; loopCounter < array.length; loopCounter++) < // get current array element int element = array[loopCounter]; // add element to sum sum += element; >System.out.println(«Sum of array elements is: » + sum); > >

Sum of array elements is: 141

for loop in this program can also be replaced with a for-each loop as shown below.

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Как сложить числа из массива java

В Java есть несколько способов найти сумму элементов массива. Например, можно использовать Stream API:

class Calculator  public static int sum(int[] numbers)  // Преобразуем массив в стрим целых чисел, а затем получаем сумму этого потока return Arrays.stream(numbers).sum(); > > int[] numbers = 1, 2, 3>; Calculator.sum(numbers); // 6 

Также можно использовать цикл, чтобы пройтись по всем элементам массива:

class Calculator  public static int sum(int[] numbers)  // Объявляем переменную для хранения суммы элементов int sum = 0; // Проходим по элементам массива и каждый к сумме for (int number: numbers)  sum += number; > return sum; > > int[] numbers = 1, 2, 3>; Calculator.sum(numbers); // 6 

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Get the Sum of an Array in Java

1. Find the Sum of an Array by Using a for Loop in Java
2. Find the Sum of an Array by Using the Stream Method in Java
3. Find the Sum of an Array by Using the reduce Method in Java
4. Find the Sum of an Array by Using the sum Method in Java
5. Find the Sum of an Array by Using the IntStream Interface in Java
6. Find the Sum of an Array by Using a Compact for Loop in Java

This tutorial introduces how to find the sum of an array in Java also lists some example codes to understand the topic.

An array is defined as a collection of similar types of elements in Java. In this article, we’ll find the sum of array elements by using some built-in methods and custom codes.

Performing this operation is very common during programming. Unfortunately, Java does not provide any specific method to get the sum of an array. So, we will use some tricks to solve this issue!

Find the Sum of an Array by Using a for Loop in Java

In this example, we used a loop to traverse each array element and get thir sum parallel. This method has a simple code that requires a single loop to get the sum. Here’s the example program:

public class SimpleTesting  public static void main(String[] args)   int arr[] = new int[] 12,34,45,21,33,4>;  int sum = 0;  for (int i = 0; i  arr.length; i++)   sum+=arr[i];  >  System.out.println("Array Sum = "+sum);   > > 

Find the Sum of an Array by Using the Stream Method in Java

In this example, we used the stream() method of the Arrays class and the parallel() method to get the sum of the array elements. We passed the lambda expression to the reduce() method that actually does the sum operation. See the example below:

import java.util.Arrays; public class SimpleTesting  public static void main(String[] args)   int arr[] = new int[] 12,34,45,21,33,4>;  int sum = Arrays.stream(arr).parallel().reduce(0,(a,b)-> a + b);  System.out.println("Array Sum = "+sum);   > > 

Find the Sum of an Array by Using the reduce Method in Java

In this example, we used the reduced() method directly with the stream of arrays and get the sum of the elements. Here’s how to do it:

import java.util.Arrays; public class SimpleTesting  public static void main(String[] args)   int arr[] = new int[] 12,34,45,21,33,4>;  int sum = Arrays.stream(arr).reduce(0,(a,b)-> a + b);  System.out.println("Array Sum = "+sum);   > > 

Find the Sum of an Array by Using the sum Method in Java

Java provides the sum() method in the Stream API to get a sum of stream sequences. Here, we passed an array to the stream and got its sum by using the sum() method. See the example below:

import java.util.Arrays; public class SimpleTesting  public static void main(String[] args)   int arr[] = new int[] 12,34,45,21,33,4>;  int sum = Arrays.stream(arr).sum();  System.out.println("Array Sum = "+sum);  > > 

Find the Sum of an Array by Using the IntStream Interface in Java

This method is another solution where you can use the Intsream interface to create a stream of array elements and utilize the sum() method to get the sum in a straightforward, single-line solution. Follow the sample code here:

import java.util.stream.IntStream; public class SimpleTesting  public static void main(String[] args)   int arr[] = new int[] 12,34,45,21,33,4>;  int sum = IntStream.of(arr).sum();  System.out.println("Array Sum = "+sum);  > > 

Find the Sum of an Array by Using a Compact for Loop in Java

In this example, we used a for loop to get the sum of array elements with an additional unique process. Here, rather than creating a loop body, we just bind up into the loop signature part. We can call it a compact loop solution. You can try it if you’re not afraid of a messy code block.

public class SimpleTesting  public static void main(String[] args)   int arr[] = new int[] 12,34,45,21,33,4>;  int sum,i;  for(sum= 0, i= arr.length - 1; 0  i; sum+= arr[i--]);  System.out.println("Array Sum = "+sum);  > > 

Related Article — Java Array

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Как найти сумму чисел из массива в java?

Да, да, я знаю, что этот код — кусок бреда, который даже близко не выполняет свою функцию, но я уже голову себе сломал и далеко я не математик (и не программист). Как же мне найти сумму чисел в массиве, при условии что длина массива может быть произвольной, а числа в нем разные, не имеющие какой либо последовательности?

9 ответов 9

Честно не понял вопроса. В начале говорится — пытаюсь получить сумму некоторых чисел. а что значит некоторых?? Если всех чисел, то это очень просто сделать:

public static void testArray() < int myArray[] = ; int sum = 0; for (int i = 0; i < myArray.length; i++) < sum = sum + myArray[i]; >System.out.println(sum); > 

Ну да, наверное всех. Не так выразился. Прощу прощения, имелось ввиду, что в массиве может быть абсолютно разные числа, которые идут не по порядку и все такое.

Нажмите только это спасибо))) Если ответ вам подошел, то заодно выбор ответа, чтобы вопрос закрылся)))

В Java 8 можно в 1 строку с помощью stream

int myArray[] = ; int total = IntStream.of(myArray).sum(); 

аналогично можно использовать класс Arrays

Метод stream имеет перегрузки для примитивных типов и обобщенный вид, что подойдет для массивов других типов.

Существует несколько способов найти сумму элементов в массиве:

Используя Java 8 Stream API (сначала с помощью метода Arrays::stream преобразовываем массив в поток целых чисел, затем получаем сумму этого потока методом Stream::sum )

int array[] = ; int sum = Arrays.stream(array).sum(); 

int array[] = ; int sum = 0; for (int element : array) sum += element; 

int array[] = ; int sum = 0; for (int i = 0; i < array.length; ++i) sum += array[i]; 

/** * Sum of all elements from 1 to 1000 */ final int sum = Stream.iterate(1, n -> n + 1).limit(1000).mapToInt(el -> el).sum(); 

Вот 3 способа, от самого примитивного, до нормального. Сильно не критикуйте, сам только учусь.

import java.util.Arrays; // сумма всех элементов массива, способ первый class BlaBlaBla1 < public static void main(String[] args) < int[] nums = ; int sum = 0; for (int i = 0; i < nums.length; i++) sum += nums[i]; System.out.println("1ый способ = " + sum); >> // сумма всех элементов массива, способ второй class BlaBlaBla2 < public static void main(String[] args) < int[] nums = ; int sum = 0; sum = Arrays.stream(nums).sum(); System.out.println("2ой способ = " + sum); > > // сумма всех элементов массива, способ третий: FOR-EACH class BlaBlaBla3 < public static void main(String[] args) < int[] nums = ; int sum = 0; for (int x : nums) sum += x; System.out.println("3ий способ = " + sum); > > 

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Sum all the elements java arraylist

This Question should be re-opened. It is valid, specific, and useful. Look at the up-votes on both Questions and Answers. Look at the newer information being added about using Java Streams for a functional solution.

8 Answers 8

double sum = 0; for(int i = 0; i < m.size(); i++) sum += m.get(i); return sum; 

double sum = 0; for(Double d : m) sum += d; return sum; 

Why do you think it is?? Does it cause Performance Degradation?? Less and Clean Code, I was hoping for!

@AnandVarkeyPhilips The 😛 on the end of comment by Barranka means she/he was joking, or half-joking. See Emoticons list: Tongue sticking out, cheeky/playful, blowing a raspberry.

@AnandVarkeyPhilips I didn't mean to offend you in any way, nor I think your solution is incorrect. Your answer is correct, and I was merely joking (thanks to BasilBourque for pointing it out)

double sum = m.stream() .mapToDouble(a -> a) .sum(); System.out.println(sum); 

a -> a is a lambda function. Before the arrow is the parameter list (a) after the arrow is the body of the function (a). It's roughly equivalent to double identity(double a) < return a >

Java 8+ version for Integer , Long , Double and Float

 List ints = Arrays.asList(1, 2, 3, 4, 5); List longs = Arrays.asList(1L, 2L, 3L, 4L, 5L); List doubles = Arrays.asList(1.2d, 2.3d, 3.0d, 4.0d, 5.0d); List floats = Arrays.asList(1.3f, 2.2f, 3.0f, 4.0f, 5.0f); long intSum = ints.stream() .mapToLong(Integer::longValue) .sum(); long longSum = longs.stream() .mapToLong(Long::longValue) .sum(); double doublesSum = doubles.stream() .mapToDouble(Double::doubleValue) .sum(); double floatsSum = floats.stream() .mapToDouble(Float::doubleValue) .sum(); System.out.println(String.format( "Integers: %s, Longs: %s, Doubles: %s, Floats: %s", intSum, longSum, doublesSum, floatsSum)); 

I haven't tested it but it should work.

public double incassoMargherita() < double sum = 0; for(int i = 0; i < m.size(); i++) < sum = sum + m.get(i); >return sum; > 

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