for loop - Calculate average in java

Question

EDIT: I've written code for the average but I don't 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 don't 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<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 < 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 right way to shape this code?

Thanks in advance.

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.