CODEWITHSUNDEEP
javaarraysdoubleaverage
user1605782
user1605782

Reputation: 111

How to manipulate arrays. Find the average. Beginner Java

I have a homework assignment and I was wondering if anyone could help me as I am new to Java and programming and am stuck on a question. The question is:

The first method finds the average of the elements of an integer array:

public double average(int[] data)

That is, given an integer array, data, calculate the average of its elements are return the average value. For example, the average of {1, 3, 2, 5, 8} is 3.8.

Here is what I have done so far: 

public double average(int[] data) {  
    int sum = 0;

    while(int i=0; i < data.length; i++) 

    sum = sum + data[i]; 
    double average = sum / data.length;; 

    System.out.println("Average value of array element is " " + average);
}

When compiling it I get an error message at the int i=0 part saying '.class expected'. Any help would be appreciated.

Upvotes: 9

Views: 146219

Answers (8)

Susikumar Pitchaimuthu
Susikumar Pitchaimuthu

Reputation: 1

  double[] numArray = { 45.3, 67.5, -45.6, 20.34, 33.0, 45.6 };
    double sum = 0.0;

    for (double num: numArray) {
       sum += num;
    }

    double average = sum / numArray.length;
    System.out.format("The average is: %.2f", average);

Upvotes: 0

skubski
skubski

Reputation: 1606

The Java 8 streaming api offers an elegant alternative:

public static void main(String[] args) {
    double avg = Arrays.stream(new int[]{1,3,2,5,8}).average().getAsDouble();

    System.out.println("avg: " + avg);
}

Upvotes: 9

Kastriot Rexhepi
Kastriot Rexhepi

Reputation: 1

Best way to find the average of some numbers is trying Classes ......

public static void main(String[] args) {
    average(1,2,5,4);

}

public static void average(int...numbers){
    int total = 0;
    for(int x: numbers){
        total+=x;
    }
    System.out.println("Average is: "+(double)total/numbers.length);

}

Upvotes: 0

Kastriot Rexhepi
Kastriot Rexhepi

Reputation: 1

If we want to add numbers of an Array and find the average of them follow this easy way! .....

public class Array {

    public static void main(String[] args) {

        int[]array = {1,3,5,7,9,6,3};
        int i=0;
        int sum=0;
        double average=0;
        for( i=0;i<array.length;i++){
            System.out.println(array[i]);
            sum=sum+array[i];
        }
        System.out.println("sum is:"+sum);
        System.out.println("average is: "+(double)sum/vargu.length);



    }

}

Upvotes: -2

mssb
mssb

Reputation: 878

Try this way

public void average(int[] data) {  
    int sum = 0;
    double average;

    for(int i=0; i < data.length; i++){
        sum = sum + data[i];
    }
    average = (double)sum/data.length;
    System.out.println("Average value of array element is " + average);    
}

if you need to return average value you need to use double key word Instead of the void key word and need to return value return average.

public double average(int[] data) {  
    int sum = 0;
    double average;

    for(int i=0; i < data.length; i++){
        sum = sum + data[i];
    }
    average = (double)sum/data.length;
    return average;    
}

Upvotes: 0

Marko Topolnik
Marko Topolnik

Reputation: 200296

Using an enhanced for would be even nicer:

int sum = 0;
for (int d : data) sum += d;

Another thing that will probably give you a big surprise is the wrong result that you will obtain from

double average = sum / data.length;

Reason: on the right-hand side you have integer division and Java will not automatically promote it to floating-point division. It will calculate the integer quotient of sum/data.length and only then promote that integer to a double. A solution would be

double average = 1.0d * sum / data.length;

This will force the dividend into a double, which will automatically propagate to the divisor.

Upvotes: 18

James
James

Reputation: 2542

Couple of problems:

The while should be a for You are not returning a value but you have declared a return type of double

double average = sum / data.length;;

sum and data.length are both ints so the division will return an int - check your types

double semi-colon, probably won't break it, just looks odd.

Upvotes: -2

CyberDem0n
CyberDem0n

Reputation: 15066

-while(int i=0; i < data.length; i++) 
+for(int i=0; i < data.length; i++)

Upvotes: 7

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