variables.md

#Variables in C

When assigning variables in C, you must specify the type.

Examples:

int main ()
{
  /* variable declaration: */
  int a, b;
  int c;
  float f;

  /* variable assignment: */
  a = 10;
  b = 20;

  c = a + b;
  printf("value of c : %d \n", c);

  f = 70.0/3.0;
  printf("value of f : %f \n", f);

  return 0;
}

The above program should output:

value of c : 30

value of f : 23.333334

##Declaration vs. Assignment

From "The C Programming Language" Section 1.2

"In C, all variables must be declared before they are used, usually at the beginning of the function before any executable statements. A declaration announces the properties of variables; it consists of a type name and a list of variables, such as

int fahr, celsius; int lower, upper, step; ...

Computation in the temperature conversion program begins with the assignment statements

`lower = 0;

upper = 300;

step = 20;

fahr = lower;`

which set the variables to their initial value."

##Weak Static Typing

C uses a weak static typing system. For more on what type systems are, and a comparison of C's type system to other languages, read the "Introduction to Programming Type Systems" from Smashing Magazine.

##Some Common Types

Type	Description
char	Typically a single octet (one byte). This is an integer type.
int	The most natural size of integer for the machine.
float	A single-precision floating point value.
double	A double-precision floating point value.
void	Represents the absence of type.

When choosing variable names, remember to avoid reserved keywords.

Reference: C Variables from TutsPoint