implemented getStatistic() method

src/main/java/core/basesyntax/WorkWithFile.java

@@ -1,7 +1,43 @@
 package core.basesyntax;
 
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+
 public class WorkWithFile {
     public void getStatistic(String fromFileName, String toFileName) {
+        int supply = 0;
+        int buy = 0;
+
+        try (BufferedReader reader = new BufferedReader(new FileReader(fromFileName))) {
+            String line;
+            while ((line = reader.readLine()) != null) {
+                String[] parts = line.split(",");
+                String operation = parts[0].trim();
+                int amount = Integer.parseInt(parts[1].trim());
+
+                if ("supply".equalsIgnoreCase(operation)) {
+                    supply += amount;
+                } else if ("buy".equalsIgnoreCase(operation)) {
+                    buy += amount;
+                }
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        writeToFile(supply, buy, toFileName);
+    }
 
+    public void writeToFile(int supply, int buy, String toFileName) {
+        int result = supply - buy;
+        try (BufferedWriter writer = new BufferedWriter(new FileWriter(toFileName))) {
+            writer.write("supply," + supply + "\n");
+            writer.write("buy," + buy + "\n");
+            writer.write("result," + result + "\n");
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 }