Calculate average in java

Question

EDIT: Ive written code for the average, but i dont know how to make it so that it also uses ints from my args.length rather than the array

I need to

Answer 1

Just some minor modification to your code will do (with some var renaming for clarity) :

double sum = 0; //average will have decimal point

for(int i=0; i < args.length; i++){
   //parse string to double, note that this might fail if you encounter a non-numeric string
   //Note that we could also do Integer.valueOf( args[i] ) but this is more flexible
   sum += Double.valueOf( args[i] ); 
}

double average = sum/args.length;

System.out.println(average );

Note that the loop can also be simplified:

for(String arg : args){
   sum += Double.valueOf( arg );
}

Edit: the OP seems to want to use the args array. This seems to be a String array, thus updated the answer accordingly.

Update:

As zoxqoj correctly pointed out, integer/double overflow is not taken care of in the code above. Although I assume the input values will be small enough to not have that problem, here's a snippet to use for really large input values:

BigDecimal sum = BigDecimal.ZERO;
for(String arg : args){
  sum = sum.add( new BigDecimal( arg ) );
}

This approach has several advantages (despite being somewhat slower, so don't use it for time critical operations):

• Precision is kept, with double you will gradually loose precision with the number of math operations (or not get exact precision at all, depending on the numbers)
• The probability of overflow is practically eliminated. Note however, that a BigDecimal might be bigger than what fits into a double or long.

Answer 2

for 1. the number of integers read in, you can just use length property of array like :

int count = args.length

which gives you no of elements in an array. And 2. to calculate average value : you are doing in correct way.

Answer 3

 System.out.println(result/count) 

you can't do this because result/count is not a String type, and System.out.println() only takes a String parameter. perhaps try:

double avg = (double)result / (double)args.length

Answer 4

I'm going to show you 2 ways. If you don't need a lot of stats in your project simply implement following.

public double average(ArrayList<Double> x) {
    double sum = 0;
    for (double aX : x) sum += aX;
    return (sum / x.size());
}

If you plan on doing a lot of stats might as well not reinvent the wheel. So why not check out http://commons.apache.org/proper/commons-math/userguide/stat.html

You'll fall into true luv!

Answer 5

public class MainTwo{
    public static void main(String[] arguments) {
        double[] Average = new double[5];
        Average[0] = 4;
        Average[1] = 5;
        Average[2] = 2;
        Average[3] = 4;
        Average[4] = 5;
        double sum = 0;
        if (Average.length > 0) {
            for (int x = 0; x < Average.length; x++) {
                sum+=Average[x];
                System.out.println(Average[x]);
            }
            System.out.println("Sum is " + sum);
            System.out.println("Average is " + sum/Average.length);
      }
   }
}

Answer 6

int values[] = { 23, 1, 5, 78, 22, 4};

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

double average = ((double) sum) / values.length;