Introduction to C Language

 

 History of C language.

The C Language was created by Dennis Ritchie at the laboratories in 1972. The UNIX system was developed in C Language between 1977 and 1979. In 1983 the American National Standards Institute (ANSI) to amend and standardized the language. In 1972 and still it is rank 2 on the TIOBE Index and 4 in IEE Spectrum Index. C was firstly developed for the UNIX Operating System. C is also called the mother of modern programing languages.

What are the key features of C programing  that makes it unique?

• Pointer mechanism.
• Functions.
• Extensible.
• Library functions.
• Compiled language.

Applications of C Language.

• Operating Systems.
• Language Compilers.
• Assemblers.
• Databases.
• Utilities.
• Text Editors.

Structure of C language.

• Documentation.
• Preprocessor Section.
• Definition.
• Global Declaration.
• Main () Function.
• Sub Program.
  
  
  

Example;

#include <stdio.h>

int main(){

  printf("Hello World!);

  return 0;

}

C New lines

• New lines are indicated by \ n.
• New line is an escape sequence.

Example;

#include <stdio.h>

int main(){

 printf("Hello World!\n");

printf("I love learning C language.");

return 0;

}

C Comments

• C comments prevent execution when testing.

Single line comments

• Single line comments start with (//).
• For short comments we use single line comments.

Example 1;

#include <stdio.h>

int main(){

// This is a comment

printf("Hello World!");

return 0;

}

Example 2;

#include <stdio.h>

int main(){

printf("Hello World!");// This is a comment.

return 0;

}

Multi-line comments

• Multi-line comments start with /* ends with */.
• For long comments we use multi-line comments.

Example;

#include <stdio.h>

int main(){

/* The code below print  the words Hello World! to the screen , and it is amazing*/

printf("Hello World!");

return 0;

}