CODEWITHSUNDEEP
java
user3288334
user3288334

Reputation: 7

Using an array list

Which code snippet calculates the sum of all the elements in even positions in an array? 

a) int sum = 0;
for (int i = 1; < values.length; i+=2)
{
sum++;
}

b) int sum = 0
for (int i = 0; i < values.length; i++)
{
sum++;
}

c) int sum = 0;
for (int i = 0; i < values.lengthl; i++)
{
sum +=values [i];
}

d) int sum = 0;
for (int i = 0; i < values.length; i + 2)
{
sum +=values [i];
}

are any of these correct? because for my answer I got 

int sum = 0;
for (int i = 0; i < values.length; i += 2)
{
sum +=values [i];
}

is my answer correct? or is it one of the multiple choices?

Upvotes: -1

Views: 59

Answers (3)

Scott Hunter
Scott Hunter

Reputation: 49920

A and B don't add elements of the array to sum; B and C process all elements. So if any of them are correct, it must be D. But since D does not change i, it cannot be right, either.

Upvotes: 0

Razib
Razib

Reputation: 11173

A small correction you are using array in your code. ArrayList is different from Array. ArrayList doesn't have a length property, it's the property of an Array. I think the answer added by Tim Biegeieisen is correct for an array.

Similary, You can do the same thing for a array list like this - 

int count=0;
int sum=0;
for(Integer i : values){
   if(count%2==0){
      sum = sum+i;
   }
   count++;
}
System.out.println(sum);

And here values is an ArrayList of Integer. Note you can not put int or any other primitive type in ArrayList. So you may declare your ArrayList used here (that is values) like - 

List<Integer> values = new ArrayList<Integer>();

Hope it will Help.
Thanks.

Upvotes: 0

Tim Biegeleisen
Tim Biegeleisen

Reputation: 522741

None of these answers appear to answer the question. Here is a code snippet which will compute the sum of all even elements of array values.

int sum = 0;
for (int i = 1; i < values.length; i = i + 2) {
    sum +=values [i];
}

You have to increment the loop variable i by 2 in order to sum only even elements. Also note that I assume the first even position is the second position in the array, which is values[1].

Upvotes: 1

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