2. History Of C
• Created By Dennis Ritchie At Bell Labs In 1972
• Originally Created To Design And Support The Unix
Operating System.
• C Compilers Are Available For Virtually Every
Platform
• In 1983 The American National Standards Institute
(ANSI) Standardized C to be called ANSI Standard C.
• ANSI C Programs That You Write Should Work With
Any ANSI C Compiler.
3. Features of C
• Efficient & Fast.
• Variety Of Data Types & Powerful Operators.
• Highly Portable.
• Well Suited For Structured Programming.
• Its Ability To Extend Itself.
• A Collection Of Functions.
4. Use Of C
• Operating Systems
• Language Compilers
• Assemblers
• Text Editors
• Print Spoolers
• Network Drivers
• Modern Programs
5. Data Types
• Different Types Of Variables Allow The Storing Different
Types Of Data, Hence The Name “Data Types”
• E.g. If You Had To Store The Numbers 10 And 10.0, C
Provides Two Different Data Types.
6. Basics Of Variables
char: A Single Byte, Holds One Character e.g. The Letter
‘a’, Although They are Stored As Integer Values
Standardized As ASCII Numbers
int: An Integer Of Fixed Length, Usually 4 bytes / 32 bits.
E.g. The Number 10 Can Be Stored In A Variable Of
Type Int.
float: Single-Precision Floating Point. e.g. The Number
10.67
double: Same As A float But With Double Precision
7. Basic Things For C
• Link Section- It Contains Header File. Mainly Two Header
Files:-
• 1 > stdio.h:-Standard Input Output Header File(For printf,
scanf, etc.)
• 2> conio.h:-Console Input Output Header File(For clrscr(),
getch(), etc.)
• Main Function:- It Contains Main Logic Of The Program.
10. C Tokens
• C Tokens Are The Basic Buildings Blocks In C Language
Which Are Constructed Together To Write A C Program.
• Each And Every Smallest Individual Units In A C Program
Are Known As C Tokens.
11. C Tokens Example Program:
• int main()
{
int x, y, total;
x = 10, y = 20;
total = x + y;
Printf (“Total = %d n”, total);
}
C Tokens Are Of Six Types
• Keywords (eg: int)
• Identifiers (eg: main, total)
• Constants (eg: 10, 20)
• Strings (eg: “total”,)
• Special symbols (eg: (), {})
• Operators (eg: +, /,-,*)
