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 write a java program that can calculate  1  the number of integers read in 2  the average value   which need not be an integer   NOTE  i dont want to calculate the average from the array but the integers in the args   Currently i have written this   int count   0      for  int i   0  i lt args length -1    i          count        System out println count            int nums     new int     23  1  5  78  22  4   double result   0    average will have decimal point           for int i 0  i  lt  nums length  i         result    nums i             System out println result count       Can anyone guide me in the right direction  Or give an example that guides me in the write way to shape this code   Thanks in advance

User · Answer

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

User · Answer

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  lt  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

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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 lt Double gt  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

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It seems old thread  but Java has evolved since then  amp  introduced Streams  amp  Lambdas in Java 8  So might help everyone who want to do it using Java 8 features     In your case  you want to convert args which is String   into double or int  You can do this using Arrays stream  lt arr gt    Once you have stream of String array elements  you can use mapToDouble s - gt  Double parseDouble s   which will convert stream of Strings into    stream of doubles  Then you can use Stream collect supplier  accumulator  combiner  to calculate average if you want to control incremental calculation yourselves  Here is some good example  If you don t want to incrementally do average  you can directly use Java s Collectors averagingDouble   which directly calculates and returns average  some examples here

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If you re trying to get the integers from the command line args  you ll need something like this   public static void main String   args        int   nums   new int args length       for int i   0  i  lt  args length  i              try               nums i    Integer parseInt args i                      catch NumberFormatException nfe                System err println  Invalid argument                            averaging code here     As for the actual averaging code  others have suggested how you can tweak that  so I won t repeat what they ve said    Edit  actually it s probably better to just put it inside the above loop and not use the nums array at all

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Instead of   int count   0  for  int i   0  i lt args length -1    i      count    System out println count         you can just  int count   args length    The average is the sum of your args divided by the number of your args   int res   0  int count   args lenght   for  int a   args    res    a    res    count    you can make this code shorter too  i ll let you try and ask if you need help   This is my first answerso tell me if something wrong

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This  for  int i   0  i lt args length -1    i      count      basically computes args length again  just incorrectly  loop condition should be i lt args length   Why not just use args length  or nums length  directly instead   Otherwise your code seems OK  Although it looks as though you wanted to read the input from the command line  but don t know how to convert that into an array of numbers - is this your real problem

User · Answer

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

User · Answer

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  gt  0                for  int x   0  x  lt  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

User · Answer

int values       23  1  5  78  22  4    int sum   0  for  int i   0  i  lt  values length  i        sum    values i    double average     double  sum    values length

[java] Calculate average in java

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