added ex8.7~8.8

ch08/README.md

@@ -26,3 +26,5 @@ putting `cin` in an error state cause to terminate. such as `eofbit`, `failbit`
 ## [Exercise 8.4](ex8_04.cpp)
 ## [Exercise 8.5](ex8_05.cpp)
 ## [Exercise 8.6](ex8_06.cpp)
+## [Exercise 8.7](ex8_07.cpp)
+## [Exercise 8.8](ex8_08.cpp)

ch08/ex8_07.cpp

@@ -0,0 +1,46 @@
+//
+//  ex8_07.cpp
+//  Exercise 8.7
+//
+//  Created by pezy on 11/28/14.
+//  Copyright (c) 2014 pezy. All rights reserved.
+//
+//  @Brief  Revise the bookstore program from the previous section to write its output to a file.
+//          Pass the name of that file as a second argument to main.
+//  @See    ex8_06.cpp
+//  @Run    give a parameter: "../data/book.txt ../data/out.txt"
+
+#include <fstream>
+#include <iostream>
+
+#include "../ch07/ex7_26.h"
+using std::ifstream; using std::ofstream; using std::endl; using std::cerr;
+
+int main(int argc, char **argv)
+{
+    ifstream input(argv[1]);
+    ofstream output(argv[2]);
+
+    Sales_data total;
+    if (read(input, total))
+    {
+        Sales_data trans;
+        while (read(input, trans))
+        {
+            if (total.isbn() == trans.isbn())
+                total.combine(trans);
+            else
+            {
+                print(output, total) << endl;
+                total = trans;
+            }
+        }
+        print(output, total) << endl;
+    }
+    else
+    {
+        cerr << "No data?!" << endl;
+    }
+
+    return 0;
+}

ch08/ex8_08.cpp

@@ -0,0 +1,46 @@
+//
+//  ex8_08.cpp
+//  Exercise 8.8
+//
+//  Created by pezy on 11/28/14.
+//  Copyright (c) 2014 pezy. All rights reserved.
+//
+//  @Brief  Revise the program from the previous exercise to append its output to its given file.
+//          Run the program on the same output file at least twice to ensure that the data are preserved
+//  @See    ex8_07.cpp
+//  @Run    give a parameter: "../data/book.txt ../data/out.txt"
+
+#include <fstream>
+#include <iostream>
+
+#include "../ch07/ex7_26.h"
+using std::ifstream; using std::ofstream; using std::endl; using std::cerr;
+
+int main(int argc, char **argv)
+{
+    ifstream input(argv[1]);
+    ofstream output(argv[2], ofstream::app);
+
+    Sales_data total;
+    if (read(input, total))
+    {
+        Sales_data trans;
+        while (read(input, trans))
+        {
+            if (total.isbn() == trans.isbn())
+                total.combine(trans);
+            else
+            {
+                print(output, total) << endl;
+                total = trans;
+            }
+        }
+        print(output, total) << endl;
+    }
+    else
+    {
+        cerr << "No data?!" << endl;
+    }
+
+    return 0;
+}