Basic Syntax

1)  Definition

A programming language is the set of instructions through which humans interact with computers. These languages are used to give instructions and commands to the computer is known as programming language. E.g. C, C++, Java etc.

a)    History/Generation

There are five generations of Programming Languages. They are:

i)       First Generation Languages (1GL)

1GL uses machine code to write instruction to interact with computer. Machine code is the binary code (0 and 1) understood by computer. It is also called Machine Level Language.

ii)     Second Generation Languages(2GL)

2GL uses assembly language to write a program. Assembly language is made up of symbolic instructions and addresses, for e.g. ADD A. It is also called Assembly Level Language.

iii)  Third Generation Language(3GL)

3GL uses structured programming language to write a program. Structured programming specifies a logical structure on the program being written to make it more efficient and easier to understand and modify. Examples of 3GL are Fortran, Basic, Turbo Pascal, C, C++.

iv)   Fourth Generation Languages (4GL)

4GL uses Non-Procedural programming language. Non procedural languages focus on what users want to do rather than how they will be doing it. It consists of statements that are similar to statements in the human language. These are used mainly in database programming and scripting. Example of these languages include, SQL, MATLAB.

v)     Fifth Generation Languages (5GL)

5GL uses Artificial Intelligence. Artificial Intelligence languages make the computer appear to communicate like a human being. Examples of fifth generation language include Mercury, OPS5, and Prolog.

b)   Classification

Programming languages can be classified as:

·         Machine level language
The first-generation programming languages are known as machine language or low-level language. The machine level language deals with only two digits 0 and 1which are also known as binary digits. As computer can only understand binary i.e. 0 and 1 these language deals with the level of abstraction.
The advantages of this languages are as follows:

o   They are translator free and can be directly executed by computer.

o   The execution speed of these program is very high.

o   These languages are efficient.

o   Memory utilization is efficient and possible to keep track of each bit of data.

The disadvantages of this language are as follows:

o   It is very difficult to develop programs

o   The programmer must have detail knowledge of hardware configuration

o   The programs are very difficult to understand by human beings

o   It is difficult to debug the programs.

o   The programs developed in this language are hardware dependent i.e. the program developed on one machine cannot be executed in another machine.

·         Assembly level language
Assembly language is one level above than machine language. The second generation languages is known as assembly language. This language uses the concept of mnemonics and symbols for writing the program. The program writing was made easier by the development of assembly language.

The advantages of assembly language are as follows

o   It is easy to develop, understand and modify the programs developed in assembly language than machine level language.

o   Less errors are generated in this language.

o   They are more standardized and easier to use than machine languages.

·         The disadvantages of assembly language are as follows

o    It is machine dependent language.

o   The programmer needs to have detail knowledge of hardware architecture.

o   This language needs additional language translator to translate the program into machine code

o    Assembly language program are still complex.

·         High Level Language

High level language is the modern language that uses formats that are similar to English. The purpose of developing high level languages was to enable people to write programs easily in their own native language environment. The generation of languages that belong to high level language are as follows:

o   Third generation language (structure oriented/ procedure oriented)

These languages belong to the third-generation language. These programs focus on the logic of the program rather than the hardware architecture. These languages are machine independent and the program developed on one computer can be used in another computer. E.g. of these languages are C, COBOL, ALGOL etc.

The advantages of these languages are as follows.

§  It is easy to learn, develop and understand the problems.

§  The programs developed on this language can be executed on other computers.

§  Program are easy to code and debug

§  Program written are less prone to error.

The disadvantages of these language are as follows

§  The program execution is slow

§  The program needs to be converted to machine code so additional language translator is required

§  Uses computer resources less efficiently

§  The memory requirement of the program written will be more compared to 1GL and 2GL

o   Fourth generation language (problem oriented/ object oriented)

This language is also termed as fourth generation language. Most of the languages are general purpose programming languages and can be used to develop any kinds of software for any platform. These programs developed in this language are based on real world scenario.

The advantages of these languages are as follows

§  These languages are easy to learn and use

§  The debugging and coding are made easier

§  It is more user friendly.

§  The programs developed in these languages are machine independent.

The disadvantages of these languages are as follows

§  The execution speed of the program is slower

§  It needs additional software to convert the program to machine code

§  The memory requirement of the program is high compared to other

§  programming languages

o   Fifth generation language (Natural Language processing)

Advantage of high-level language

o   Language are user friendly

o   Easier to learn

o   Easier to maintain

o   They are problem oriented rather than machine based

Disadvantages of high-level language

o   It takes additional translation time to translate the source to machine code.

o   High level programs are comparatively slower than low level programs.

o   Easier to maintain

o   Compared to low level programs, they are generally less memory efficient.

o   Cannot communicate directly with the hardware.

o   Structure oriented language

Out of these language generation C belongs to the third generation so it is called middle level language as well as high level language.

c)    Compiler Interpreter and Assembler

Compiler Interpreter and Assembler falls under the category of language translator. Language Translators A program written in high-level language is called as source code. To convert the source code into machine code, translators are needed. A translator takes a program written in source language as input and converts it into a program in target language as output. It also detects and reports the error during translation.

Roles of translator are

·         Translating the high-level language program input into an equivalent machine language program.

·         Providing diagnostic or error messages wherever the programmer violates specification or rules of the high-level language program.

i)       Different type of translators

The different types of translator are as follows:

(1)   Compiler

Compiler is a translator which is used to convert programs in high-level language to low-level language. It translates the entire program and also reports the errors in source program encountered during the translation. 

(2)   Interpreter

Interpreter is a translator which is used to convert programs in high-level language to low-level language. Interpreter translates line by line and reports the error once it encountered during the translation process. It directly executes the operations specified in the source program when the input is given by the user. It gives better error diagnostics than a compiler

(3)   Assembler

Assembler is a translator which is used to translate the assembly language code into machine language code.

d)   List of high-level programming languages

High level language are the languages which are easy to understand and can be written in English language. The development of program is easy using this language. The example of high-level language are as follows:

• C 
• C++
• JAVA
• PHP
• BASIC
• .NET

e)    Syntax and semantics errors

A syntax error is like a grammatical error or an error in spelling where you made a new, unrecognizable word. So, basically you made a program the computer can’t read or understand somewhere. Program doesn’t execute when it has these types of errors. So, these kinds of errors are easily traceable and can be corrected by beginners of a program.

For e.g.:

int a = 5 // semicolon is missing

So, compiler cannot process from here as it requires semicolon so it shows error. A sematic error is the error in the programming logic which computer can understand but the program gives wrong output. The computer executes the program but the output is wrong. These kinds of error are complex in nature and only expert programmers are able to trace it in a huge program.

For e.g. c = a + b; for this statement we mistakenly placed c = a-b; here the error is in the logic of the program so program is right but the output produced by program is wrong.

f)      Program control structures

Program control structures defines the flow of program. They define the way the program logic to flow in the program. There are three program control structures they are:

·         Sequence
In this control structure the flow of program flows in sequential manner. The logic defines the program to flow on the line by line basis. So in these control structures the length of the program will be high and program becomes complex due to same repetition of code. This will be addressed in upcoming chapters

·         Selection
In this control structure the flow of program flows on the basis of selection. The program has the capability to directly jump to the function selected by user. The length of the program is reduced by the use of selection techniques in a program. The most frequently used selection procedures in C programming are switch, goto, and label.

·         Iteration
In this control structure the flow of a program is designed in such a way the program continuously operates until the condition given by the user is satisfied. The program keeps updating its input and output automatically as defined by the user. These techniques reduce the length of a program and it is very efficient. The iteration is also termed as looping. The loops available in C programming are for,while, do…while.

i)       Program Design Tools

The program design tools are the tools required to develop a program. During designing the program various tools are required to design the program such as

·         Algorithm

·         Flowchart

·         Pseudocode 

(1)   Algorithm

An algorithm is a set of steps of operations to solve a problem performing calculation, data processing, and automated reasoning tasks. An algorithm is an efficient method that can be expressed within finite amount of time and space. An algorithm is the best way to represent the solution of a particular problem in a very simple and efficient way. If we have an algorithm for a specific problem, then we can implement it in any programming language, meaning that the algorithm is independent from any programming languages.

The main characteristics of algorithms are as follows

·         Algorithms must have a unique name

·         Algorithms should have explicitly defined set of inputs and outputs

·         Algorithms are well-ordered with unambiguous operations

·         Algorithms halt in a finite amount of time. Algorithms should not run for infinity, i.e., an algorithm must end at some point

Algorithm for adding two numbers

Step 1: start

Step2: input two numbers x and y

Step3: read two numbers x and y

Step4: z=x+y

Step5: display result z

Step6: stop

(2)   Flowchart

A flowchart is simply a graphical representation of steps. It shows steps in a sequential order, and is widely used in presenting flow of algorithms, workflow or processes. Typically, flowchart shows the steps as boxes of various kinds, and their order by connecting them with arrows. 

(3)   Pseudocode

Pseudocode gives a high-level description of an algorithm without the ambiguity associated with plain text but also without the need to know the syntax of a particular programming language. The running time can be estimated in a more general manner by using Pseudocode to represent the algorithm as a set of fundamental operations which can then be counted.

Pseudocode for finding the area of rectangle:

Input length breadth

Calculate area= length* breadth

Output: area 

C programming, created by Dennis Ritchie at Bell Labs in the early 1970s, stands as a foundational language in the world of computing. With its efficiency, portability, and versatility, C has remained a stalwart tool for programmers across diverse fields.

As a procedural language, C offers a concise syntax and powerful features suitable for both low-level memory management and high-level abstraction. Its direct interaction with hardware makes it invaluable for system programming, embedded systems, and performance-critical applications like gaming.

Furthermore, C's influence extends to numerous other languages, including C++, Java, and Python, making it an essential language to master for any programmer.

In this introduction, we'll explore the basics of C programming, providing a solid foundation for your journey into the world of software development.

 

#include <stdio.h>

int main(){

printf("Namaste!");

return 0;}

 

This is Basic Syntax for the C programming. Whenever you start programming then you must include the library and for the Standard Input and output you have to put stdio.h library. Above Example shows the following things:

You are including standard input output library.

You are using Main() function

You are Printing "Namaste!"

You are informing CPU that after the execution of program no more resource will be in use.(return 0; indicates no more resource will be used.)

<stdio.h> is basic library file that include following functions.

1.       printf(): Prints formatted output to the console.

2.       scanf(): Reads formatted input from the console.

3.       fgets(): Reads a string from a file stream.

4.       fputs(): Writes a string to a file stream.

5.       fgetc(): Reads a character from a file stream.

6.       fputc(): Writes a character to a file stream.

7.       fread(): Reads data from a file stream into a buffer.

8.       fwrite(): Writes data from a buffer into a file stream.

9.       ftell(): Reports the current file position indicator for a file stream.

10.   fopen(): Opens a file and returns a pointer to a file stream.

11.   fclose(): Closes a file stream.

12.   fflush(): Flushes the output buffer of a file stream.

13.   setbuf(): Sets the buffer for a file stream.

14.   setvbuf(): Sets the buffering mode for a file stream.

15.   setlocale() - sets the locale for formatted input/output functions 

16.   fprintf(): Prints formatted output to a file stream.

17.   fscanf(): Reads formatted input from a file stream.

18.   tmpfile(): Creates a temporary file.

19.   tmpnam(): Generates a unique temporary file name.

20.   remove(): Deletes a file.

21.   rename(): Renames a file.

22.   freopen(): Reopens a file stream with a specified mode.

23.   getchar(): Reads a character from the standard input.

24.   putchar(): Writes a character to the standard output.

25.   gets(): Reads a string from the standard input.

26.   puts(): Writes a string to the standard output.

27.   feof(): Checks if the end-of-file indicator is set for a file stream.

28.   ferror(): Checks if the error indicator is set for a file stream.

29.   clearerr(): Clears the error and end-of-file indicators for a file stream.

30.   fseek() - sets the file position indicator to a location in a file stream.

31.   ftell() - returns the current value of the file position indicator for a stream.

32.   fgetc() - reads the next character from a stream.

33.   vprintf() - prints formatted output with a variable argument list to stdout 

34.   vfprintf() - writes formatted output with a variable argument list to a file

35.   vsprintf() - writes formatted output with a variable argument list to a string 

36.   vscanf() - reads formatted input with a variable argument list from stdin

37.   vfscanf() - reads formatted input with a variable argument list from a file 

38.   vsscanf() - reads formatted input with a variable argument list from a string