Calculate average or take in an ArrayList as a parameter to a function

Question

Is there a built-in method to calculate the average of an integer ArrayList?

If not, can I make a function that will do that by taking in the name of the ArrayList and r

Answer 1

If you want to computer later one more than the average I propose Colt library developed at CERN which supports many statistic functions. See BinFunctions1D and DoubleMatrix1D. An alternative (with a recent code basis) may be commons-math:

DescriptiveStatistics stats = new DescriptiveStatistics();
for( int i = 0; i < inputArray.length; i++)
{
    stats.addValue(inputArray[i]);
}
double mean = stats.getMean();