C - System Programming

The C language was originally designed from 1969 to 1972, by Dennis Ritchie to program the Unix operating system.
The goal of C was to be portable.

C Features

A C program is a set of functions that return or not a value, and global variables.
Functions and variables have prototypes in header files for external use.
The programmer must manage itself the memory, using pointers and functions to allocate of free fields of memory.
It is portable with some restrictions, additional variable types for exemple, are specific to compilers.

Why to use it?

C has known success thanks to the liberty if offers to programmers. The drawback is the difficulty to debug the programs. It is fast, and a large collection of APIs is available.

Description of the C language

Data structures:

Control structures:

• if ... else
• switch ... case ... default
• while
• for
• do ... while
• break, continue, return
• goto

Some symbols:

The while loop:

while(x < y)
{
   ... statements ...
}

Defining a function:

int name(char *x, int y)
{
   ... statements ...

   return(z);
}

C Sites and tools

• Introduction to C
  First C curse.
• LCC
  A 32 bits C compiler with IDE and manual (Win).
• Turbo C 2.01
  A free C compiler with textual IDE. You may have to search on the site among archives to found it..(Win)
• Cint
  C and C++ interpreter.
• Development of C
  Article by D. Ritchie.

Libraries

• Graphic 32
  A graphical library for C++ builder and Kylix.
• SDI Framework
  Library to start an application for Windows without MFC.

Sample code

string s = "demo" + "trail";
int l = s.length();
for(int i = 0; i < l; i++)
{
   char c = s[i];
   printf("%c\n", c);
}