adding all sections

lectures/01_introduction/README.md

@@ -4,12 +4,12 @@
 - Crash Course in C++ Syntax
 - Getting Started in C++ & STL, C++ Syntax, STL Strings
 
-## Transitioning from Python to C++ (from CSCI-1100 Computer Science 1)
+## 1.1	Transitioning from Python to C++ (from CSCI-1100 Computer Science 1)
 
 - Python is a great language to learn the power and flexibility of programming and computational problem solving.  This semester we will work in C++ and study lower level programming concepts, focusing on details including efficiency and memory usage.
 - Outside of this class, when working on large programming projects, you will find it is not uncommon to use a mix of programming languages and libraries.  The individual advantages of Python and C++ (and Java, and Perl, and C, and UNIX bash scripts, and ... ) can be combined into an elegant (or terrifyingly complex) masterpiece.
 
-## Compiled Languages vs. Interpreted Languages
+## 1.2	Compiled Languages vs. Interpreted Languages
 
 - C/C++ is a *compiled language*, which means your code is processed
 (compiled & linked) to produce a low-level machine language
@@ -52,7 +52,7 @@ make.  Even long-time C++ programmers make mistakes in syntax, and
 with practice you will become familiar with the compiler's error
 messages and how to correct your code.
 
-## A Sample C++ Program: Find the Roots of a Quadratic Polynomial
+## 1.3	A Sample C++ Program: Find the Roots of a Quadratic Polynomial
 
 ```cpp
 #include <iostream>   // library for reading & writing from the console/keyboard
@@ -119,7 +119,7 @@ int main() {
 }
 ```
 
-## Some Basic C++ Syntax
+## 1.4	Some Basic C++ Syntax
 
 - Comments are indicated using // for single line comments and /* and */ for multi-line comments.
 - #include asks the compiler for parts of the standard library and other code that we wish to use (e.g. the
@@ -127,3 +127,171 @@ input/output stream function std::cout).
 - int main() is a necessary component of all C++ programs; it returns a value (integer in this case) and it
 may have parameters.
 - { }: the curly braces indicate to C++ to treat everything between them as a unit.
+
+## 1.5	The C++ Standard Template Library, a.k.a. “STL”
+
+- The standard template library contains types and functions that are important extensions to the core C++ language.
+We will use the standard template library to such a great extent that it will feel like part of the C++ core language.
+std is a namespace that contains the standard template library.
+
+- I/O streams are the first component of the standard template library that we see. std::cout (“console output”) and
+std::endl (“end line”) are defined in the standard template library header file, iostream.
+
+## 1.6	A few notes on C++ vs. Java
+
+- In Java, everything is an object and everything “inherits” from java.lang.Object. In C++, functions can
+exist outside of classes. In particular, the main function is never part of a class.
+
+- Source code file organization in C++ does not need to be related to class organization as it does in Java. On
+the other hand, creating one C++ class (when we get to classes) per file is the preferred organization, with the
+main function in a separate file on its own or with a few helper functions.
+
+## 1.7	Variables and Types
+
+- A variable is an object with a name. A name is C++ identifier such as “a”, “root_1”, or “success”.
+- An object is computer memory that has a type. A type (e.g., int, float, and bool) is a structure to memory
+and a set of operations.
+- For example, a float is an object and each float variable is assigned to 4 bytes of memory, and this memory
+is formatted according IEEE floating point standards for what represents the exponent and mantissa. There
+are many operations defined on floats, including addition, subtraction, printing to the screen, etc.
+- In C++ and Java the programmer must specify the data type when a new variable is declared. The C++
+compiler enforces type checking (a.k.a. static typing). In contrast, the programmer does not specify the type
+of variables in Python and Perl. These languages are dynamically-typed — the interpreter will deduce the data
+type at runtime.
+
+## 1.8	Expressions, Assignments and Statements
+
+Consider the statement: root_pos = (-b + sqrt_radical) / float(2*a);
+
+- The calculation on the right hand side of the = is an expression. You should review the definition of C++
+arithmetic expressions and operator precedence from any reference textbook. The rules are pretty much the
+same in C++ and Java and Python.
+- The value of this expression is assigned to the memory location of the float variable root_pos. Note also that
+if all expression values are type int we need a cast from int to float to prevent the truncation of integer
+division.
+
+## 1.9	Conditionals and IF statements
+
+- The general form of an if-else statement is
+
+```cpp
+	if (conditional-expression)
+		statement;
+	else
+		statement;
+```
+
+- Each statement may be a single statement, such as the continue statement above, or multiple statements
+delimited by {. . .}.
+
+## 1.10	Functions and Arguments
+
+- Functions are used to:
+  - Break code up into modules for ease of programming and testing, and for ease of reading by other people
+(never, ever, under-estimate the importance of this!).
+  - Create code that is reusable at several places in one program and by several programs.
+- Each function has a sequence of parameters and a return type. The function prototype below has a return
+type of bool and five parameters.
+
+```cpp
+	bool find_roots(int a, int b, int c, float &root_pos, float &root_neg);
+```
+- The order and types of the parameters in the calling function (the main function in this example) must match
+the order and types of the parameters in the function prototype.
+
+## 1.11 Value Parameters and Reference Parameters
+
+- What’s with the & symbol on the 4th and 5th parameters in the find_roots function prototype?
+- Note that when we call this function, we haven’t yet stored anything in those two root variables.
+```cpp
+	float root_1, root_2;
+	bool success = find_roots(my_a,my_b,my_c, root_1,root_2);
+```
+- The first first three parameters to this function are value parameters.
+  – These are essentially local variables (in the function) whose initial values are copies of the values of the corresponding argument in the function call.
+  – Thus, the value of my_a from the main function is used to initialize a in function find_roots.
+  – Changes to value parameters within the called function do NOT change the corresponding argument in the calling function.
+- The final two parameters are reference parameters, as indicated by the &.
+  - Reference parameters are just aliases for their corresponding arguments. No new objects are created.
+  - As a result, changes to reference parameters are changes to the corresponding variables (arguments) in the calling function.
+- In general, the “Rules of Thumb” for using value and reference parameters:
+  - When a function (e.g., check_root) needs to provide just one simple result, make that result the return value of the function and pass other parameters by value.
+  - When a function needs to provide more than one result (e.g., find_roots, these results should be returned using multiple reference parameters.
+- We’ll see more examples of the importance of value vs. reference parameters as the semester continues.
+
+## 1.12	for & while Loops
+
+- Here is the basic form of a for loop:
+```cpp
+	for (expr1; expr2; expr3)
+		statement;
+```
+  – expr1 is the initial expression executed at the start before the loop iterations begin;
+  – expr2 is the test applied before the beginning of each loop iteration, the loop ends when this expression evaluates to false or 0;
+  – expr3 is evaluated at the very end of each iteration;
+  – statement is the “loop body”
+ Here is the basic form of a while loop:
+```cpp
+	while (expr)
+		statement;
+```
+  - expr is checked before entering the loop and after each iteration. If expr ever evaluates the false the loop is finished.
+
+## 1.13	C-style Arrays
+
+- An array is a fixed-length, consecutive sequence of objects all of the same type. The following declares an array with space for 15 double values. Note the spots in the array are currently uninitialized.
+```cpp
+	double a[15];
+```
+- The values are accessed through subscripting operations. The following code assigns the value 3.14159 to location i=5 of the array. Here i is the subscript or index.
+```cpp
+	int i = 5;
+	a[i] = 3.14159;
+```
+- In C/C++, array indexing starts at 0.
+- Arrays are fixed size, and each array knows NOTHING about its own size. The programmer must keep track of the size of each array. (Note: C++ STL has generalization of C-style arrays, called vectors, which do not have these restrictions.)
+
+## 1.14 Python Strings vs. C chars vs. C-style Strings vs. C++ STL Strings
+
+- Strings in Python are immutable, and there is no difference between a string and a char in Python. Thus, ’a’ and "a" are both strings in Python, not individual characters. In C++ & Java, single quotes create a character type (exactly one character) and double quotes create a string of 0, 1, 2, or more characters.
+- A “C-style” string is an array of chars that ends with the special char ’\0’. C-style strings (char* or char[]) can be edited, and there are a number of helper functions to help with common operations. However...
+- The “C++-style” STL string type has a wider array of operations and functions, which are more convenient and more powerful.
+
+## 1.15	About STL String Objects
+
+- A string is an object type defined in the standard library to contain a sequence of characters.
+- The string type, like all types (including int, double, char, float), defines an interface, which includes construction (initialization), operations, functions (methods), and even other types(!).
+- When an object is created, a special function is run called a “constructor”, whose job it is to initialize the
+object. There are several ways of constructing string objects:
+  – By default to create an empty string: std::string my_string_var;
+  – With a specified number of instances of a single char: std::string my_string_var2(10, ' ');
+  – From another string: std::string my_string_var3(my_string_var2);
+- The notation my_string_var.size() is a call to a function size that is defined as a member function of the string class. There is an equivalent member function called length.
+-  Input to string objects through streams (e.g. reading from the keyboard or a file) includes the following steps:
+  1. The computer inputs and discards white-space characters, one at a time, until a non-white-space character is found.
+  2. A sequence of non-white-space characters is input and stored in the string. This overwrites anything that was already in the string.
+  3. Reading stops either at the end of the input or upon reaching the next white-space character (without reading it in).
+- The (overloaded) operator ’+’ is defined on strings. It concatenates two strings to create a third string, without changing either of the original two strings.
+- The assignment operation ’=’ on strings overwrites the current contents of the string.
+- The individual characters of a string can be accessed using the subscript operator [] (similar to arrays).
+  – Subscript 0 corresponds to the first character.
+  – For example, given std::string a = "Susan"; Then a[0] == 'S' and a[1] == 'u' and a[4] == 'n'.
+- Strings define a special type string::size_type, which is the type returned by the string function size()
+(and length()).
+  – The :: notation means that size type is defined within the scope of the string type.
+  – string::size_type is generally equivalent to unsigned int.
+  – You may see have compiler warnings and potential compatibility problems if you compare an int variable to a.size().
+
+## 1.16	C++ vs. Java
+
+- Standard C++ library std::string objects behave like a combination of Java String and StringBuffer objects. If you aren’t sure of how a std::string member function (or operator) will behave, check its semantics or try it on small examples (or both, which is preferable).
+- Java objects must be created using new, as in:
+```java
+String name = new String("Chris");
+```
+This is not necessary in C++. The C++ (approximate) equivalent to this example is:
+```cpp
+std::string name("Chris");
+```
+Note: There is a new operator in C++ and its behavior is somewhat similar to the new operation in Java. We will study it in a couple weeks.
+