Wednesday, September 3, 2014

ProfitCalculator

Problem:
Overview:

Calculate the profit margin given an array of items.

Java Source:
```01: public class ProfitCalculator {
02:
03:     public int percent(String[] items) {
04:
05:         // Holds running totals of the customer and stores costs.
06:         float totalCustCost = 0f;
07:         float totalStoreCost = 0f;
08:
09:         for (String s : items) {
10:
11:             // Splits the item into customer and store components
12:             String[] costs = s.split(" ");
13:
14:             totalCustCost += Float.parseFloat(costs[0]);
15:             totalStoreCost += Float.parseFloat(costs[1]);
16:         }
17:
18:         float margin = ((totalCustCost - totalStoreCost) / totalCustCost) * 100;
19:
20:         return (int) margin;
21:     }
22: }
```
Notes:

Not much to this problem. totalCustCost and totalStoreCost are created to keep a running total of the customer and stores costs. We loop through each of the items in the input array, and update the totals as each item is processed. At the end just use the formulat ((customer cost - store cost ) / customer cost) * 100 to get the final profit.

When processing each item, the String method split() is used to divide the customer and store portions. Then Float.parseFloat() is used to convert the string representation into a float.

The return value must be an int, so we must cast this since a float to an int could lose precision. However, fortunately, that's just what the problem statement calls for.