Standart deviation in c

[blu3jam]

Write a program to find and display the Largest, Smallest, Average, standard deviation and the Sum of all numbers entered from the keyboard.The data entry should end with a Sentinel Value. After finishing ask if the user wants to continue entering new set of numbers or not.

http://www.ee.hacettepe.edu.tr/~alkar/ELE108/labs/homeworks/hw1.ht1.gif , where X indicates average



My question is can we write this program without using arrays ? Does anybody have a suggestion ?

[DefaultName]

Not really. It will make your life easier to use arrays. It will help if there is a known number of samples, perhaps you can ask the user before you create the array and then once you know the value, create it with that many locations.

Also, it's A TON easier to go through hundreds or even thousands of x values with an array (using either a for or while loop). Imagine wanting to store 4,000 x values. That means you need 4,000 manually defined variables. Manually, as in you type x_1, x_2, x_3, ..., x_3999, x_4000.

Use an array. Use loops. This will make your life easier.

[rohanprabhu]

no way you should be doing any statistical programming without using arrays/lists/something like that.

[blu3jam]

I figured it out now ,instead of saving inputs separately by using arrays, I can convert deviation formula another form

http://upload.wikimedia.org/math/5/2/a/52af1f8f6cb9c93b9ce829b3ac57af8f.png
http://upload.wikimedia.org/math/9/c/3/9c3cd5442f1745f7f7ee2cff3174a6e0.png

Now , it's easy to calculate. Thanks

[D H]

Easy to calculate, but potentially inaccurate. Computers don't have infinite precision. What you did works mathematically but loses accuracy when performed using numbers as typically represented on computers (e.g., doubles or floats in the C language).