Declarations and Initializations (2)

Variable names in C are made up of letters (upper and lower case) and digits. The underscore character ("_") is also permitted. Names must not begin with a digit.

Examples of valid (but not very descriptive) C variable names:
=> foo
=> Bar
=> BAZ
=> foo_bar
=> _foo42
=> _
=> QuUx

External Linkage-> means global, non-static variables and functions.
Internal Linkage-> means static variables and functions with file scope.
None Linkage-> means Local variables.

fmod(x,y) - Calculates x modulo y, the remainder of x/y.
This function is the same as the modulus operator. But fmod() performs floating point divisions.

Example:

#include 
#include 

int main ()
{
  printf ("fmod of 3.14/2.1 is %lf\n", fmod (3.14,2.1) );
  return 0;
}

Output:
fmod of 3.14/2.1 is 1.040000