review ch01-05

Author: pezy

README.md

@@ -1,14 +1,14 @@
 ##C++ Primer 5th Answers
 
-[![GitHub issues](https://img.shields.io/github/issues/Mooophy/Cpp-Primer.svg)](https://github.com/pezy/CppPrimer/issues)
+[![GitHub issues](https://img.shields.io/github/issues/pezy/CppPrimer.svg)](https://github.com/pezy/CppPrimer/issues)
 [![GitHub license](https://img.shields.io/badge/license-CC0-blue.svg)](https://raw.githubusercontent.com/pezy/Cpp-Primer/master/LICENSE)
 [![](https://img.shields.io/badge/%E4%B8%AD%E6%96%87-%E8%AE%A8%E8%AE%BA%E5%8C%BA-yellowgreen.svg)](https://github.com/ReadingLab/Discussion-for-Cpp)
 
 ### Notes
 
-- **g++** and **clang++** are recommended. Visual Studio 2013 may be used as well, but up to June 2015, Visual Studio has not implemented all c++11 features yet.
+- Use `GCC 4.9+`, `Clang 3.4+`, `MSVC 14+`, and [others](http://en.cppreference.com/w/cpp/compiler_support).
 - Use `-std=c++11`(recommend: `-pedantic -Wall`) flag for compiling.
-- If any bug caught, please [let me know](https://github.com/pezy/Cpp-Primer/issues/new), thanks.
+- Have you discovered incorrect information? [Submit](https://github.com/pezy/CppPrimer/issues/new).
 
 ### Contents
 

ch01/README.md

@@ -1,28 +1,32 @@
+# Chapter 1. Getting Started
+
 ##Exercise 1.1
 
 > Review the documentation for your compiler and determine what file naming convention it uses. Compile and run the main program from page 2.
 
 ### Windows
 
-![windows](https://db.tt/XGeGsg7O)
+![windows](https://cloud.githubusercontent.com/assets/1147451/8334465/a87e3528-1aca-11e5-877d-c610f087fc40.png)
+
 
 ### Linux
 
-![Linux](https://db.tt/2xKWuztU)
+![Linux](https://cloud.githubusercontent.com/assets/1147451/8334480/c160e75c-1aca-11e5-92d5-7d0a05fbf493.png)
+
 
 ##Exercise 1.2
 
 > Exercise 1.2: Change the program to return -1. A return value of -1 is often treated as an indicator that the program failed. Recompile and rerun your program to see how your system treats a failure indicator from main.
 
 ###Windows
 
-![windows](https://db.tt/DIJd9eZb)
+![image](https://cloud.githubusercontent.com/assets/1147451/8335952/72179d5e-1ad3-11e5-84ff-e924816e64a3.png)
 
 ###Linux
 
-![linux](https://db.tt/lhzXhpCt)
+![image](https://cloud.githubusercontent.com/assets/1147451/8335963/8debbc5e-1ad3-11e5-9761-013139d291d8.png)
 
-**255**? why? please look at [this](http://www.tldp.org/LDP/abs/html/exitcodes.html)
+**255**? why? check [this](http://www.tldp.org/LDP/abs/html/exitcodes.html)
 
 ##Exercise 1.3
 > Write a program to print Hello, World on the standard output.
@@ -32,8 +36,8 @@
 
 int main()
 {
-  std::cout << "Hello, World" << std::endl;
-  return 0;
+    std::cout << "Hello, World" << std::endl;
+    return 0;
 }
 ```
 
@@ -111,7 +115,8 @@ int main()
 
 Compiled result(g++):
 
-![result](https://db.tt/CqQKu8GQ)
+![ex1_7](https://cloud.githubusercontent.com/assets/1147451/8334581/4fb4a408-1acb-11e5-98e3-54c0929198ec.png)
+
 
 ##Exercise 1.8
 
@@ -122,12 +127,11 @@ std::cout << "*/";
 std::cout << /* "*/" */;
 std::cout << /* "*/" /* "/*" */;
 ```
-> After you’ve predicted what will happen, test your answers by compiling a
-program with each of these statements. Correct any errors you encounter.
+> After you’ve predicted what will happen, test your answers by compiling a program with each of these statements. Correct any errors you encounter.
 
 Compiled result(g++):
 
-![result](https://db.tt/mrL9hDCS)
+![ex1_8](https://cloud.githubusercontent.com/assets/1147451/8334603/6aa321e0-1acb-11e5-988a-57e87a53b141.png)
 
 Corrected? just added a quote:
 ```cpp
@@ -142,13 +146,12 @@ Output:
     /**/ */ /*
 ```
 
-##[Exercise 1.9](ex1_9.cpp)
+##[Exercise 1.9](ex1_09.cpp)
 ##[Exercise 1.10](ex1_10.cpp)
 ##[Exercise 1.11](ex1_11.cpp)
 
 ##Exercise 1.12
-> What does the following for loop do? What is the final value
-of sum?
+> What does the following for loop do? What is the final value of sum?
 ```cpp
 int sum = 0;
 for (int i = -100; i <= 100; ++i)
@@ -158,9 +161,9 @@ for (int i = -100; i <= 100; ++i)
 the loop sums the numbers from -100 to 100. the final value of sum is zero.
 
 ##Exercise 1.13
-> Rewrite the exercises from § 1.4.1 (p. 13) using for loops.
+> Rewrite the exercises from 1.4.1 (p. 13) using for loops.
 
-Ex1.9:
+**Ex1.9**:
 ```cpp
 #include <iostream>
 
@@ -176,166 +179,144 @@ int main()
 }
 ```
 
-Ex1.10:
+**Ex1.10**:
 ```cpp
 #include <iostream>
 
 int main()
 {
     for (int i=10; i>=0; --i)
-        std::cout << i << std::endl;
+        std::cout << i << " ";
+    std::cout << std::endl;
 
     return 0;
 }
 ```
 
-Ex1.11:
+**Ex1.11**:
 ```cpp
 #include <iostream>
 
 int main()
 {
-    int val_small = 0, val_big = 0;
+    int small = 0, big = 0;
     std::cout << "please input two integers:";
-    std::cin >> val_small >> val_big;
+    std::cin >> small >> big;
 
-    if (val_small > val_big) {
-        int tmp = val_small;
-        val_small = val_big;
-        val_big = tmp;
+    if (small > big) {
+        int tmp = small;
+        small = big;
+        big = tmp;
     }
 
-    for (int i = val_small; i <= val_big; ++i)
-        std::cout << i << std::endl;
+    for (int i = small; i <= big; ++i)
+        std::cout << i << " ";
+    std::cout << std::endl;
 
     return 0;
 }
 ```
 
 ##Exercise 1.14
-> Compare and contrast the loops that used a for with those
-using a while. Are there advantages or disadvantages to using either form?
+> Compare and contrast the loops that used a `for` with those using a `while`. Are there advantages or disadvantages to using either form?
+
+- Advantage of `for` and disadvantage of `while`:
+    - Locality, the variable in the scope of the loop.
+    - Pattern happens so often: using a variable in a condition and incrementing that variable in the body.
+- Advantage of `while` and disadvantage of `for`:
+    - Clear when there is only one static condition.
+    - Readable when the global variables incremented in the body.
 
-If you need a pattern which is using a variable in a condition and incrementing that variable in the
-body. You should use `for` loop. Else the `while` loop is more simple.
+-----
 
-Want to know more? look at [this](http://stackoverflow.com/questions/1600282/guideline-while-vs-for)
+[A similar question on Stack Overflow](http://stackoverflow.com/questions/2950931/for-vs-while-in-c-programming)
 
 ##Exercise 1.15
-> Write programs that contain the common errors discussed in
-the box on page 16. Familiarize yourself with the messages the compiler
-generates.
+> Write programs that contain the common errors discussed in the box on page 16. Familiarize yourself with the messages the compiler generates.
 
-**JUST READ IT!**
+Self-training.
 
 ##Exercise 1.16
 
-> Write your own version of a program that prints the sum of a set of integers read from cin.
-
-Many people confused about this exercise, such as [this](http://www.cplusplus.com/forum/beginner/104169/) and [this](http://stackoverflow.com/questions/17841424/how-to-write-this-while-loop-as-a-for-loop).
-
-In my opinion, the exercise aim to write the program without "**END-OF-FILE**".
-
-**BUT**, the [code](http://www.cplusplus.com/forum/beginner/104169/#msg561450) in first link is not correct.
-
-The following are my own version:
+> Write your own version of a program that prints the sum of a set of integers read from `cin`.
 
 ```cpp
 #include <iostream>
 
 int main()
 {
-    int limit = 0, sum = 0, value = 0;
-    std::cout << "How many integers would you like to enter?";
-    std::cin >> limit;
-
-    // assume we don't know what is EOF(End-Of-File).
-    while (std::cin >> value && (--limit != 0))
+    int sum = 0;
+    for (int value = 0; std::cin >> value; )
         sum += value;
-
-    std::cout << sum + value << std::endl;
-
+    std::cout << sum << std::endl;
     return 0;
 }
 ```
 
-Watch out for "sum + value" in the `cout` line.
-
 ##Exercise 1.17
 
 > What happens in the program presented in this section if the input values are all equal? What if there are no duplicated values?
 
-If the input values are all equal, it will print a line which shows the count of the number you input.
-
-If there are no duplicated values, when different values input, a new line will be printed if you click `Enter`.
+If all equal, the count will be printed out. If there are no duplicated values, A new line will be printed when `Enter` clicked.
 
 ##Exercise 1.18
 
 > Compile and run the program from this section giving it only equal values as input. Run it again giving it values in which no number is repeated.
 
-![run](https://db.tt/F38zExnq)
+![ex1_18](https://cloud.githubusercontent.com/assets/1147451/8335404/0861c478-1ad0-11e5-8083-c05a0cd9e758.png)
+
 
 ##Exercise 1.19
 
 > Revise the program you wrote for the exercises in § 1.4.1 (p. 13) that printed a range of numbers so that it handles input in which the first number is smaller than the second.
 
-Yes, we should use `if` to judge which is bigger.
-
-review this [code](https://github.com/pezy/Cpp-Primer/blob/master/ch01/ex1_11.cpp)
+check [ex1_11.cpp](https://github.com/pezy/Cpp-Primer/blob/master/ch01/ex1_11.cpp)
 
 ##Exercise 1.20
 
 > http://www.informit.com/title/032174113 contains a copy of Sales_item.h in the Chapter 1 code directory. Copy that file to your working directory. Use it to write a program that reads a set of book sales transactions, writing each transaction to the standard output.
 
-[Here](ex1_20.cpp) is the code.
+check [code](ex1_20.cpp).
 
-**You need to enable C++11 support in your compiler.
-With GCC and Clang, this can be done with the `-std=c++11` option.**
+Test it using the `data`/`book.txt`:
 
-**(Never say it again.)**
+![ex1_20](https://cloud.githubusercontent.com/assets/1147451/8335638/8f5c2bca-1ad1-11e5-9c51-288382710df2.png)
 
-How to test it? use the `book.txt` in `data` folder. And do it like this:
-
-![run](https://db.tt/fm8iHtkF)
 
 ##Exercise 1.21
-> Write a program that reads two Sales_item objects that have the same ISBN and produces their sum.
+> Write a program that reads two `Sales_item` objects that have the same ISBN and produces their sum.
 
-The program should check whether the objects have the same ISBN.(Have a look at 1.5.2, surprise!)
+The program should check whether the objects have the same ISBN.(check 1.5.2)
 
 [Code](ex1_21.cpp)
 
 ##Exercise 1.22
 
 > Write a program that reads several transactions for the same ISBN. Write the sum of all the transactions that were read.
 
-Tips: this program will appear in the section 1.6.
+Tip: this program will appear in the section 1.6.
 
-[Here](ex1_22.cpp) is the code.
+[Code](ex1_22.cpp).
 
-![run](https://db.tt/UlkuvpAS)
+![ex1_22](https://cloud.githubusercontent.com/assets/1147451/8335700/d85ee22c-1ad1-11e5-9612-1155145606c1.png)
 
 ##Exercise 1.23
 > Write a program that reads several transactions and counts
 how many transactions occur for each ISBN.
 
 Tip: please review the `1.4.4`.
 
-[Here](ex1_23.cpp) is the code.
+[Code](ex1_23.cpp).
 
 ##Exercise 1.24
-> Test the previous program by giving multiple transactions
-representing multiple ISBNs. The records for each ISBN should be grouped
-together.
+> Test the previous program by giving multiple transactions representing multiple ISBNs. The records for each ISBN should be grouped together.
 
-You can use data/book.txt as the records.
+Use `data`/`book.txt` as the records.
 
-![run](https://db.tt/EeDI7lvN)
+![ex1_24](https://cloud.githubusercontent.com/assets/1147451/8335734/0fbefbbc-1ad2-11e5-9df3-fa1203dffb42.png)
 
-##Exercise 1.25
-> Using the Sales_item.h header from the Web site,
-compile and execute the bookstore program presented in this section.
 
-It is the same as Exercise 1.22.
+##Exercise 1.25
+> Using the `Sales_item.h` header from the Web site, compile and execute the bookstore program presented in this section.
 
-![run](https://db.tt/C6OOPuzA)
+![ex1_25](https://cloud.githubusercontent.com/assets/1147451/8335742/1efb475c-1ad2-11e5-9484-69ae44b79385.png)

ch01/ex1_9.cpp renamed to ch01/ex1_09.cpp

@@ -4,20 +4,21 @@
 
 int main()
 {
-    int val_small = 0, val_big = 0;
+    int small = 0, big = 0;
     std::cout << "please input two integers:";
-    std::cin >> val_small >> val_big;
+    std::cin >> small >> big;
 
-    if (val_small > val_big) {
-        int tmp = val_small;
-        val_small = val_big;
-        val_big = tmp;
+    if (small > big) {
+        int tmp = small;
+        small = big;
+        big = tmp;
     }
 
-    while (val_small <= val_big) {
-        std::cout << val_small << std::endl;
-        ++val_small;
+    while (small <= big) {
+        std::cout << small << " ";
+        ++small;
     }
+    std::cout << std::endl;
 
     return 0;
 }