1. Programming Languages

2. Classification and distinctive features
Procedural Language
A term used in contrast to declarative language to describe a language where the programmer specifies an explicit sequences of steps to follow to produce a result.
Common procedural languages include Basic, Pascal and C.
Declarative Language
Declarative languages describe relationships between variables in terms of functions or inference rules and the language executor (interpreter or compiler) applies some fixed algorithm to these relations to produce a result.
Common declarative languages include logic programming languages such as Prolog

3. Classification and distinctive features
Object-oriented Language
A programming languages and techniques based on the concept of an "object" which is a data structure (abstract data type) encapsulated with a set of routines, called "methods" which operate on the data. Operations on the data can only be performed via these methods, which are common to all objects, which are instances of a particular "class".
Common declarative languages include C++ and Java.

4. Classification and distinctive features
Visual Programming
Visual programming environments provides graphical or iconic elements, which can be manipulated by the user in an interactive way according to some specific spatial grammar for program construction.
Common declarative languages include Visual Basic and Visual C++.
Query Language
A language in which users of a database can (interactively) formulate requests and generate reports. The best known is SQL

5. Tracing simple programs in C++
A simple C++ program
#include <iostream.h>
preprocessor directive(s)
main() {   // A simple C++ program   int x, y, sum;   cout << "A program which adds two integers\n";   cout << "Enter 1st integer: ";   cin >> x;   cout << "Enter 2nd integer: ";   cin >> y;   sum = x + y;   cout << "Sum is " << sum << endl;   return 0; }
program body

6. syntax of C++
The preprocessor directive ‘#include <iostream.h>’ can be found in almost all C++ programs.  It provides subprograms to process standard input and standard output.
Use cin for standard input and cout for standard output.
Declarative statements can be put in anywhere of the program body.
Use a pair of double quotation marks (") to enclose a string.
Special characters:
\t (horizontal tab)
\n (newline character)
\\ (the backslash \)
\" (the double quotation mark ")

7. Data types, variables and variable assignment
Variables are case-sensitive.
Common simple data types
int (integer)
short (16-bit integer)
long (32-bit integer)
char (character)
float (single precision floating-point number)
double (double precision floating-point number)
The type modifier unsigned indicates that the variable cannot hold negative numbers.
The reserved word typedef is used to define a new data type.
C++ uses the equal sign (=) for assignment, e.g. ‘x = 4;’. (Use ‘==’ as ‘equal to’ in C++.)
Initialisation can be done in the declarative statements, e.g. ‘int x = 4;’
Mixed-mode assignment is possible: