Is there possibility of sum of ArrayList without looping

Question

Is there possibility of sum of ArrayList without looping?

PHP provides sum(array) which will give the sum of array.

The PHP code is like

$a = array(2, 4, 6, 8); echo "sum(a) = " . array_sum($a) . "\n"; 

I wanted to do the same in Java:

List tt = new ArrayList(); tt.add(1); tt.add(2); tt.add(3); 

Answer 1

Once java-8 is out (March 2014) you'll be able to use streams:

If you have a List<Integer>

int sum = list.stream().mapToInt(Integer::intValue).sum(); 

If it's an int[]

int sum = IntStream.of(a).sum(); 

Answer 2

Then write it yourself:

public int sum(List<Integer> list) {      int sum = 0;        for (int i : list)          sum = sum + i;       return sum; }