C++ Programming Basics Quiz

C++ Programming Basics

• In C++, all elements of the standard library are declared within the std namespace.
• A namespace is a logical container for grouping unique entities (blocks).
• Every C++ program MUST have a function named main.
• The body of a function starts with an opening brace ({) and ends with a closing brace (}).
• Each instruction in C++ must end with a semicolon (;).
• The cout object is used to display output on the screen.
• Strings (text) in C++ are enclosed in double quotes (").
• The return statement ends function execution.
• Returning a zero value from main indicates that the program executed successfully.

Data Types and Variables

• Comments are for human readers and are ignored by the compiler.
  • They are used to explain code functionality, variables, functions, authorship, and development dates.
  • Single-line comments start with //.
  • Multi-line comments start with /* and end with */.
• Reserved Words (Keywords) are words that have special meaning in C++ and cannot be used as variable names.
  • Examples include: int, float, double, char, const, void, return.
• Variables are containers that store the results of C++ operations, allowing them to be used in other operations.
• Variable Identifiers are names for variables.
  • They consist of letters, digits, and underscores (_).
  • They must start with a letter or an underscore.
  • C++ is case-sensitive, meaning NUMBER and number are different.
  • cout and cin are two predefined identifiers. You can technically redefine them, but it is generally not recommended.
• Variable Declaration is how a variable is created.
  • It defines the variable's name and type.
  • The format is: type variableName; (for example: int myVariable;)
  • You can declare multiple variables of the same type with commas: int variable1, variable2, variable3;
• Variable Assignment is how a variable is given an initial value.
  • The assignment operator = is used.
  • Examples:
    • Counter = 1; (assigns 1 to the variable Counter)
    • Result = 100 + 200; (assigns the result of the sum to the variable Result)
    • X = X + 1; (increments the value of X by 1)
• Data Types define the kind of values a variable can hold and the operations that can be performed on them.
• Simple Data Types are basic data types that represent fundamental values:
  • Integral (integers, whole numbers): char, short, int, long, bool.
  • Floating-Point (decimal numbers): float, double.
  • Enumeration Type: User-defined data type used to create a set of named constants.
• Integral Data Types categorize integers:
  • char: single character (e.g., 'A', 'a', '0', '*', '+', '$', '&', ' ').
  • short: small integer values.
  • int: standard integer values.
  • long: large integer values.
  • bool: logical values (either true or false).
  • unsigned char, unsigned short, unsigned int, unsigned long: versions of the integral types that allow only non-negative values (0 or positive).
• int Data Type can represent positive or negative integers, without decimals.
  • Examples: -6728, 0, 78, +763.
• bool Data Type represents logical (Boolean) values:
  • true or false.
• char Data Type is used for single characters, including letters, digits, and special symbols.
  • Each character is enclosed in single quotes (e.g., 'A', '*').
  • A blank space is considered a character (' ').
  • char is the smallest integral type.
• ASCII (American Standard Code for Information Interchange) is a standard coding system used almost universally.
  • It assigns numerical values to characters (0 to 255), allowing computers to represent and process text.
  • Each character has a unique ASCII code.
  • The ASCII table displays these character codes.
• UNICODE is a newer coding system that expands ASCII.
  • It supports a much wider range of characters, including those used in various languages around the world.
• ASCII Table is a standardized representation of ASCII codes where each character corresponds to a specific number.
• char values are int values, meaning you can assign integer values to variables of type char.
• Floating-Point Types represent decimal numbers:
  • float can handle a wide range of numbers but has lower precision than double.
  • double provides more precise representations of decimal numbers.
• float Precision: Limited to 6 or 7 significant digits.
• double Precision: Up to 15 significant digits.
• Scientific Notation is a way to express very large or very small numbers:
  • 300000000  3E8
  • 6.62607 X 10-34  6.62607E-34
• Conversion Between int and float:
  • You can always convert an integer (int) to a floating-point number (float) without losing accuracy.
  • Converting a floating-point number to an integer can result in loss of precision.
• string Data Type is used for sequences of characters.
  • It can be empty, containing no characters (null).
  • Each character within a string has a position (starting from 0).
  • The string's length is the number of characters it contains.
  • Example: string x = “Hello World20 ?”; // length is 15 characters.