Lesson 3

• Program – a collection of text that commands a computer to perform algorithms
• Programming Language – A collection of rules and syntax used to describe a program, employed based on the user’s objective and the computer's format and usage
• Programming – An act of writing algorithms while utilizing a programming language
• Low-Level Language – programming languages written in a format that is easy for computers to interpret, examples include Machine language and Assembly language
• High-Level Language – programming languages written in a format that resembles human language and diminishes user awareness of hardware devices, examples include C, C++, Java, Python, etc.
• C++ Language – a general-purpose programming language with a bias towards systems programming that supports data abstraction, is a better C, supports generic and object-oriented programming, and is case sensitive
• Parts of a C++ Language:

  • Pre-processor directive instructs the compiler to locate the file that contains code for the <iostream> library
  • Allows you to use cout and endl without the prefix std::
  • Entry point for the application when program execution starts
  • Closing curly brace
  • Opening curly brace
  • Body of the program where the content is located or written
  • Used to end a function or method when a value is expected to be sent back to a caller
• Processing a C++ Program:

  • Step 1: SOURCE CODE / SOURCE PROGRAM: a program written in a high-level language, created in the text editor, must be saved in a file with the extension .cpp
  • Step 2: PREPROCESSOR DIRECTIVES: statements that begin with the symbol # processed by a preprocessor program
  • Step 3: COMPILER: checks the source program for syntax errors and translates the entire source program into the equivalent machine language with an executable format
  • Step 4: LINKER: combines the object program with other programs in the library to create the executable code
  • Step 5: LOADER: loads the executable program into main memory for execution
  • Step 6: EXECUTION: process by which a computer or virtual machine executes the instructions of a computer program
• Terms to Remember:

  • Value: representation of an entity that can be manipulated by a program and is classified based on different data types
  • Variable: a one-word name that points to a value
• C++ Data Types:

  • Data Type: determines the type of data that a variable can hold
  • Primitive Data Type: built-in or predefined data types that can be used directly by the developer to declare variables
  • INTEGER: Keyword int, deals with integers or numbers without a decimal part
  • FLOATING-POINT: Keyword float, single precision data type that deals with decimal numbers, max number of decimal places: 7
  • DOUBLE FLOATING POINT: Keyword double, double precision data type that deals with decimal numbers, max number of decimal places: 15
• Primitive Data Types:

  • Double: double precision data type dealing with decimal numbers, max 15 decimal places
  • Boolean: used to store Boolean or logical values like True or False
• Character Data Types:

  • Char: represents characters (letters, digits, special symbols)
  • Wide Character (wchar_t): character data type with a size greater than the normal 8-bit datatype
• Storage and Values of Data Types:

  • Char: 1 byte, signed -128 to 127, unsigned 0 to 255
  • Bool: 1 byte, true and false
  • Int: 4 bytes, signed -2,147,483,648 to 2,147,483,647, unsigned 0 to 4,294,967,295
  • Short: 2 bytes, signed -32,768 to 32,767, unsigned 0 to 65,535
  • Long: 4 bytes, signed -2,147,483,648 to 2,147,483,647, unsigned 0 to 4,294,967,295
• String:

  • A sequence of zero or more characters enclosed in double quotation marks
  • Determining the length of the string includes counting any spaces
• C Strings:

  • One-dimensional arrays of characters terminated by a null character ‘\0’
  • Example: char greeting[] = “Hello”;
• String Functions:

  • strcat: concatenates string s2 onto the end of string s1
  • strncat: concatenates string s2 onto the end of string s1 up to n characters
  • strcmp: compares two strings lexicographically and returns values: 0 if s1 and s2 are the same, less than 0 if s1 < s2, greater than 0 if s1 > s2
  • strcpy: copies string s2 into string s1
  • strncpy: copies string s2 into string s1 up to n characters
  • strlen: returns the length of a string
• Derived Data Types:

  • Function: block of code defined to perform a specific task
  • Array: collection of items stored at continuous memory locations
  • Pointers: symbolic representation of addresses enabling call-by-reference and dynamic data structures
  • Reference: alternative name for an existing variable
• Abstract Data Types:

  • User-defined data types like class, structure, union, and enumeration
• Terms to Remember:

  • Operators: symbols for calculation, relationship, comparison, and operations on operands
  • Constant: memory location with content not allowed to change during program execution
• C++ Tokens:

  • Token: smallest individual unit of a program
  • Special Symbols: operators in the form of mathematical symbols, punctuation marks, or two characters regarded as a single symbol
• C++ Operators:

  • Arithmetic Operators: used for mathematical operations like addition, subtraction, multiplication, and division
  • Increment and Decrement Operators:
  • Pre-increment: ++variable
  • Post-increment: variable++
  • Pre-decrement: --variable
  • Post-decrement: variable-
• Increment and decrement operators in C++:

  • Pre-increment: ++variable
  • Post-increment: variable++
  • Pre-decrement: --variable
  • Post-decrement: variable--
• Relational operators in C++ are used to compare values and return True or False according to the condition
• Logical operators in C++ are used to perform logical AND, OR, and NOT operations
• Assignment operators in C++ are used to assign values to variables
• C++ tokens are the smallest individual units of a program written in any language
• Identifiers in C++ consist of letters, digits, and the underscore character (_), and must begin with a letter or underscore
• Legal identifiers in C++ can include words like first, conversion, payrate, counter1, but cannot have spaces or special characters like + or begin with a digit
• C++ statements:

  • Declaration statements are used to declare things such as variables
  • Executable statements perform calculations, manipulate data, create output, accept input, and more
• Output statements in C++ involve the output stream, where bytes flow from main memory to the device (display) using the stream insertion operator
• Expressions in programming are combinations of values, variables, and operators
• Casting in C++:

  • Implicit Type Coercion automatically changes a value of one data type to another
  • Cast Operator (static_cast) is an explicit type conversion to avoid implicit type coercion
• Escape sequences in C++ are special characters used in control strings to modify the format of an output
• Three-step rule in programming:

  1. Visualize the problem by creating an algorithm using a flowchart

  2. Translate into pseudocodes

  3. Write the equivalent C++ codes for each pseudocode