completing saveReport() function.

src/main/java/ReportGenerator.java

@@ -1,5 +1,6 @@
 import java.io.File;
 import java.io.FileNotFoundException;
+import java.io.FileWriter;
 import java.io.IOException;
 import java.util.List;
 import java.util.Scanner;
@@ -82,25 +83,22 @@ public class ReportGenerator {
 
     public void saveReport()
     {
-        // TODO:
-        // 1. Build a formatted report string
-        // 2. Include:
-        //      - total quantity
-        //      - total final cost
-        //      - total discount value
-        //      - total invalid lines
-        // 3. Create/open output report file (name it report.txt)
-        // 4. Write report string into file
-        // 5. Handle file writing exceptions
-        // 6. Close writer resources
-
-        /* Example Structure
-        ========= SALES REPORT =========
-        Total Quantity Sold: 42
-        Total Final Cost: $1520.75
-        Total Discount Value: $230.50
-        Invalid Rows: 3
-        ================================
-        */
+        String report =
+                        "===== SALES REPORT =====\n" +
+                        "Total Quantity: " + totalQuantity + "\n" +
+                        "Total Final Cost: $" + String.format("%.2f", totalFinalCost) + "\n" +
+                        "Total Discount: $" + String.format("%.2f", totalDiscountValue) + "\n" +
+                        "Invalid Lines: " + InvalidLines + "\n" +
+                        "=========================\n";
+        try
+        {
+            FileWriter fileWriter = new FileWriter("output.txt");
+            fileWriter.write(report);
+            fileWriter.close();
+        }
+        catch (IOException e)
+        {
+            System.out.println("Error in outputting report: " + e.getMessage());
+        }
     }
 }