Programming languages in information technology are used to create computer programs that are used to solve programming tasks or implement specific algorithms.
Program, Syntax and Semantics
A computer program is a set of instructions that complies syntaxes and semantics.
Similar to grammar for any human language, these computer programming languages adhere to certain syntaxes (form) and semantics (meaning). They instruct computers to perform specific set of instructions.
Evolution of Programming Languages
There are many programming languages in history starting with machine language, also called first-generation programming languages or 1GL, and it comprised direct numeric form instructions to computer.
Second-generation programming languages or 2GL are built using specific instruction set in a human readable format called as Assembly language and these were tied to specific computer.
Later, when the concept of compilers began, the third-generation or high-level programing programming languages or 3GL have originated. They used human understandable programmable instructions which were turned into machine code through the compiler. FORTRAN was the first functional implementation language.
This 3GL introduced a necessity for low-level programming languages or system programming languages. Thus, many 4GL programming languages have started i.e. Array programming (APL), Structured procedure programming (ALGOL), Functional programming (LISP), Object-oriented programming (Simula, Smalltalk, C++ etc), Structured static programming language (C), Logic programming language (Prolog), etc.
Next, the growth of Internet paved way for various new languages that led to the growth of 5GL. UNIX script (Perl) was released to create dynamic websites. Java became popular for server side programming owing to its ‘write once and run anywhere’ principle.
Note that the higher level languages such as “C”, C++, Pascal, COBOL, FORTRAN, ADA and Java are called “compiled languages”.
Programming Concepts
A program is a set of instructions which performs a specific task. For example, how to calculate the average salary of personnel, amount that customer withdrew from ATM, etc. can be executed by a computer. To achieve these tasks, a computer requires a programmable instruction to execute in a Central Processing Unit (CPU).
Computer program written in any programming language has:
A source code, which is a human readable format, written by the programmer or developer.
A machine code, that is obtained once compiler translates the source code into machine instructions. This machine code is executed by interpreters.
Programming Models
There are two different programming models: Structured Oriented Programming and Object Oriented Programming.
In Structured programming, code is executed one after another; whereas an object oriented programming is based on the concept of objects which contains data and procedures or methods.
Structure Oriented
A programming language in which the entire logic of the program is written by dividing it into smaller units or modules is called as structured programming language. C language is one of the structured programming language which is been widely used. In C language, the smaller units are referred to as functions.
A function is always written separately to perform a specific task. A function has a unique name. It is called for execution in the main body of the program with reference to its name.
Object Oriented
Object oriented approach to programming consists of implementing a system as collection of objects that have state and behavior interacting with each other to achieve expected functionalities. The flow of data and program is used to communicate by passing messages/data.
C++ and Java languages are examples of Object-Oriented Programming languages.
The object is the basic entity in Object Oriented Programming (OOP). An object can be defined as any real-world entity that has a well-defined structure and behavior. A pen, a car, etc. can be some real-world examples of objects. OOP identifies all the objects the programmer wants to manipulate and how they are related to each other i.e. data modelling.
Concepts to Create Programs
First Program
In general, “Hello world” Program is considered as the first program in any programming language. We get the output as Hello World in the terminal. Let us see Hello World program in different languages
- C language:
Program:
#include <stdio.h>
int main()
{
printf (“Hello, World!”);
}
The output is: Hello, World!
Note that printf() a function used to print the Hello, World!
2. Java Language:
Program:
public class HelloWorld {
public static void main (String []args) {
System.out.println(“Hello, World!”);
}
}
Output is Hello, World!
Note that println() function is used to write Hello, World!
3. Python:
Program:
print “Hello, World!”
Output is Hello, World!
Here print function is used to write Hello, World!
Data Types
In programming languages, the type of the data which is used in processing is represented by a data type. If the data types are not specific, then an error may occur.
We have two different typed programming languages.
Statically typed
A Statically typed programming languages is defined as the language in which the variables always have a specific type and the type of the variable cannot be changed. Large amount of your time is required to fix the program and compile it. C language is one of the examples of statically typed language
Dynamic Typed
A Dynamic typed programming language is defined as the language in which the variable has no specific type and the type of the variable can be changed.
Different programming languages have different keywords to specify different data types.
For example, C and Java programming languages we use int to specify integer data and char to specify a character data type whereas in python, the data types are dynamically allocated.
Data Types in C, C++ and Java
C, C++ and Java support almost the same set of data types. Java supports additional data types compared to C and C++. Let us see some common data types that are there in C, C++ and Java languages.
- char: For character and strings
- int: For integers
- float: For the numbers with decimal such as amounts, quotients.
These data types are called primitive data types. We can use these data types to build more complex data types, which are called user-defined data type, for example a string will be a sequence of characters.
Data Types in Python
Python has seven basic data types but here we do not make use of any keyword to specify a particular data type.
- Numbers
- String
- List
- Tuple
- Dictionary
- Boolean
- Sets
Here, Numbers store numerical information such as integers and floating point, Strings store ordered sequence of characters, List stores ordered sequence of object, Tuples are similar to list i.e. it also stores objects.
The only difference between the lists and tuples are tuples are immutable whereas the lists are mutable. Dictionary stores unordered key value pair. Sets store unordered collection of unique objects and Booleans store logical value indicating True or False.
Variables
Variables are the names we allocate to the computer memory locations which are used to store values in a computer program.
Three simple steps to be followed for creating a variable
- Creation of variables with some names.
- Store the values in those variables.
- Use the variables in the program to retrieve the values.
Different programming languages have different ways for allocating a variable.
Creating variables in C language
Creating variables or declaring variables in C programming. C is a staticaly typed language.
#include <stdio.h>
int main()
{
int a;
a=10;
}
In the above program, a variable ‘a’ is created and it stores an integer value. This variable ‘a’ is now assigned with integer value 10.
Similarly, we can create different variable to store different data types.
char c; //to store a character value in variable c//
float f; //to store a float value in variable f//
Variables in Java
The variable creation in java in similar to that of in C. Java is a statically typed language.
For example,
public class DemoJava {
public static void main(String []args) {
int a;
a = 10;
System.out.println(“Value of a = ” + a);
}
}
In the above program, a variable ‘a’ is created and it is allocated with the value 10
Variables in Python
Since python is a dynamically typed languages there is no need of mentioning the data type before the variable.
For example,
a = 10
In the above program, a variable ‘a’ is declared and assigned with the value 10.
Control Statements
In computer programming, the decision making is critical. In many cases we face situations where we will be given two or more options and we will have to select an option based on the given conditions. In situation like this, the control statements are used.
if…else statement
An if statement can be followed by an optional else statement, which executes when the Boolean expression is false.
The syntax of an if else statement in C programming language is
if(boolean_expression) {
//this block executes if Boolean is true//
}
else {
//this block executes if Boolean is false//
}
For example:
#include <stdio.h>
int main() {
int x = 5;
if( x >9 ) {
printf( “A”);
}
else {
printf( “B”);
}
}
Output– B
if…elseif…else statement
If there are many conditions, then if statement can be followed by an optional else if…else statement.
Syntax:
if(boolean_expression 1)
{
/* This block executes if boolean expression 1 is true */
}
else if( boolean_expression 2)
{
/* This block executes if boolean expression 1 is true */
}
else if( boolean_expression 3)
{
/* This block executes if boolean expression 1 is true */
} else {
/* Executes when the none of the above condition is true */
}
The Switch Statement
The switch case construct is used in situations where based on the value of the variable certain action is to be taken.
Syntax:
switch(expression)
{
case 1:
statement(s);
break;
case 2:
statement(s);
break;
default :
statement(s);
}
The expression used in a switch statement must give an integer value, which will be compared for equality with different cases given. Wherever an expression value matches with a case value, the body of that case will be executed and finally, the switch will be terminated using a break statement.
Control Statements in Java
Similar to C, even in java if, if…else, if…elseif…else, and switch statements are the control statements.
public class DemoJava {
public static void main(String []args) {
int x = 5;
if( x > 9) {
System.out.println( “A “);
}
else if( x < 3) {
System.out.println( “B”);
}
else if( x < 3 && x > 9 ) {
System.out.println( “C”);
}
}
}
Output: C
Control Statements in Python
if, if…else, if…elif…else, and switch statements are the control statements in python.
Example program in python:
x =5
if x > 9:
print “A”
elif x < 3:
print “B”
elif x < 9 and x > 3:
print “C”
Output – C
Functions
A Function can be defined as a block of code that can be reused. They provide better modularity for our application and a high degree of code reusing.
Some examples of functions are printf() and main() in C language. These are called built-in functions since they are already created in the language. We also can write functions. These functions are called as user defined functions.
There are two types of functions:
- Single level Function
- Multiple Level Function
Note: Methods, subroutines, procedures, etc. are the other names for a function.
Pointers
A pointer is a variable, which contains the address of some other variable in the memory. A pointer may point to variable of any data type. A pointer can point any portion of the memory
A pointer variable is declared as:
Datatype *<Pointer variable name>
The pointer variable can initialized as:
<pointer variable name> = &<Variable name to which the pointer points to>
- The & returns the address of the variable.
- The * before a pointer name gives the value of the variable to which it is pointing.
Arrays, Slices and Maps
An array is a sequence of elements of same length or size. An array contains many slices; in other words, a slice is a segment of an array.
Maps is another concept of array and contains similar key value pairs. It is also called a hash table or a dictionary.
The syntax and declaration of these components vary with programming language.
Structs and Interfaces
Structs simplify the structure of a program. They contain named fields. Once they are declared, they should be initialised to make them active.
Interfaces contain the properties of object that you have declared in your program. Interfaces play a key role in object oriented programming in making the code reusable and simple.
Concurrency
The concept is specifically used for designing web servers, web pages and web design. Concurrency lets you define the sequence or simultaneous execution of tasks defined in your program.
Packages
A package is a namespace that is analogous to folder in a computer. It contains set of related classes and interfaces.
Testing
Programming may be complex when the task to be performed is complex. It can involve many functions, routines and subroutines, declarations, initializations and all, that makes the program prone to errors. Thus, software testers test the code before the code is actually deployed, for finding out bugs and issues. This process is called testing.
Once the testing is done, programmers fix the issues as per the test results and make the code safer for real time use.
The benefits of taking professional Programming Assignment Help are not unknown to many. There is no doubt that annexing professional assistance is a great way to deal with the strenuous academic situation. Choosing the right assistance at right time is the key to achieve top grades.
