Merge pull request pezy#80 from pezy/master

Finished Chapter 8.

README.md

@@ -24,9 +24,9 @@
   - [Chapter 4. Expressions](ch04/README.md)
   - [Chapter 5. Statements](ch05/README.md)
   - [Chapter 6. Functions](ch06/README.md)
-  - [Chapter 7. Classes](ch07)
-  - [Chapter 8. The IO Library](ch08)
+  - [Chapter 7. Classes](ch07/README.md)
 - Part II: The C++ Library
+  - [Chapter 8. The IO Library](ch08/README.md)
   - [Chapter 9. Sequential Containers](ch09)
   - [Chapter 10. Generic Algorithms](ch10)
   - [Chapter 11. Associative Containers](ch11)

ch08/README.md

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+# Chapter 8. The IO Library
+
+## Exercise 8.1:
+>Write a function that takes and returns an istream&. The function should read the stream until it hits end-of-file. The function should print what it reads to the standard output. Reset the stream so that it is valid before returning the stream.
+
+```cpp
+istream& func(istream &is)
+{
+    std::string buf;
+    while (is >> buf)
+        std::cout << buf << std::endl;
+    is.clear();
+    return is;
+}
+```
+
+## [Exercise 8.2](ex8_02.cpp)
+
+## Exercise 8.3:
+>What causes the following while to terminate?
+```cpp
+while (cin >> i) /*  ...    */
+```
+
+putting `cin` in an error state cause to terminate. such as `eofbit`, `failbit` and `badbit`.
+
+## [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)
+## [Exercise 8.9](ex8_09.cpp)
+## [Exercise 8.10](ex8_10.cpp)
+## [Exercise 8.11](ex8_11.cpp)
+
+## Exercise 8.12:
+>Why didn’t we use in-class initializers in PersonInfo?
+
+Cause we need a aggregate class here. so it should have no in-class initializers.
+
+## [Exercise 8.13](ex8_13.cpp)
+
+## Exercise 8.14:
+>Why did we declare entry and nums as const auto &?
+
+- cause they are all class type, not the built-in type. so **reference** more effective.
+- output shouldn't change their values. so we added the `const`.

ch08/ex8_02.cpp

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+//
+//  ex8_02.cpp
+//  Exercise 8.2
+//
+//  Created by pezy on 11/27/14.
+//  Copyright (c) 2014 pezy. All rights reserved.
+//
+//  @Brief  Test your function by calling it, passing cin as an argument
+
+#include <iostream>
+using std::istream;
+
+istream& func(istream &is)
+{
+    std::string buf;
+    while (is >> buf)
+        std::cout << buf << std::endl;
+    is.clear();
+    return is;
+}
+
+int main()
+{
+    istream& is = func(std::cin);
+    std::cout << is.rdstate() << std::endl;
+    return 0;
+}

ch08/ex8_04.cpp

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+//
+//  ex8_04.cpp
+//  Exercise 8.4
+//
+//  Created by pezy on 11/9/14.
+//  Copyright (c) 2014 pezy. All rights reserved.
+//
+//  @Brief  Write a function to open a file for input and read its contents into a vector of strings, 
+//          storing each line as a separate element in the vector. 
+
+#include <fstream>
+#include <string>
+#include <vector>
+#include <iostream>
+
+using std::vector; using std::string; using std::ifstream; using std::cout; using std::endl;
+
+void ReadFileToVec(const string& fileName, vector<string>& vec)
+{
+    ifstream ifs(fileName);
+    if (ifs)
+    {
+        string buf;
+        while (std::getline(ifs, buf))
+            vec.push_back(buf);
+    }
+}
+
+int main()
+{
+    vector<string> vec;
+    ReadFileToVec("../data/book.txt", vec);
+    for (const auto &str : vec)
+        cout << str << endl;
+    return 0;
+}
+

ch08/ex8_05.cpp

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+//
+//  ex8_05.cpp
+//  Exercise 8.5
+//
+//  Created by pezy on 11/9/14.
+//  Copyright (c) 2014 pezy. All rights reserved.
+//
+//  @Brief  Rewrite the previous program to store each word in a separate element.
+//  @See    ex8_04.cpp 
+
+#include <fstream>
+#include <string>
+#include <vector>
+#include <iostream>
+
+using std::vector; using std::string; using std::ifstream; using std::cout; using std::endl;
+
+void ReadFileToVec(const string& fileName, vector<string>& vec)
+{
+    ifstream ifs(fileName);
+    if (ifs)
+    {
+        string buf;
+        while (ifs >> buf)
+            vec.push_back(buf);
+    }
+}
+
+int main()
+{
+    vector<string> vec;
+    ReadFileToVec("../data/book.txt", vec);
+    for (const auto &str : vec)
+        cout << str << endl;
+    return 0;
+}
+

ch08/ex8_06.cpp

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+//
+//  ex8_06.cpp
+//  Exercise 8.6
+//
+//  Created by pezy on 11/27/14.
+//  Copyright (c) 2014 pezy. All rights reserved.
+//
+//  @Brief  Rewrite the bookstore program from ¡ì7.1.1 (p.256) to read its transactions from a file. 
+//          Pass the name of the file as an argument to main (¡ì6.2.5, p.218). 
+//  @See    ex7_26.h (use the Sales_data)
+//  @Run    give a parameter: "../data/book.txt"
+//  @Output 0-201-78345-X 5 110
+//          0-201-78346-X 9 839.2 
+
+#include <fstream>
+#include <iostream>
+
+#include "../ch07/ex7_26.h"
+using std::ifstream; using std::cout; using std::endl; using std::cerr;
+
+int main(int argc, char **argv)
+{
+    ifstream input(argv[1]);
+
+    Sales_data total;
+    if (read(input, total))
+    {
+        Sales_data trans;
+        while (read(input, trans))
+        {
+            if (total.isbn() == trans.isbn())
+                total.combine(trans);
+            else
+            {
+                print(cout, total) << endl;
+                total = trans;
+            }
+        }
+        print(cout, total) << endl;
+    }
+    else
+    {
+        cerr << "No data?!" << endl;
+    }
+
+    return 0;
+}

ch08/ex8_07.cpp

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+//
+//  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;
+}