Calculate average in java

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.


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.

ShareFollowedited May 24 ’17 at 13:20answered Aug 10 ’11 at 9:02Thomas83.4k1212 gold badges115115 silver badges149149 bronze badges

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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;

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