Hmmmm.

As I mentioned, I was planning to add to my 'Learn C By Example' page on my website. I wanted to provide a very basic introduction to some of C's basic variable types.

Here is what I had (see example program below)... what distinction would you recommend I make between a float and a double? Would it be safe to say that on most systems a doulbe would be bigger than a float and could therefore provide a higher level of precision. Anyway, tell me what you think... here is the example I put together. I know the program doesn't do anything useful... it is only meant as an introduction to some of C's basic variable types.

Code:
/*      Variables Program
 *      ====================
 *      Purpose: Demonstrating the creation and assignment of some simple variables.
 *      Author: Eddie Meyer
 *      Date: 5 DEC 2005
 */
#include <stdio.h>

int main(void)
{
	/* ============================================================
	 * Let's create (declare) some variables of different types.
	 * I've tried to give an indication of what each variable
	 * will hold by choosing variable names that essentially
	 * describe what they will be used for.  You are always
	 * recommended to try and do this to help others understand
	 * your code.  Oftentimes, it is you that will need reminding
	 * of what each variable in your program does.  Choosing
	 * descriptive variable names will prove extremely valuable
	 * to you when you come to review your code a year or two
	 * down the line.
	 * ============================================================
	 */


	/* Create a string (a sequence of characters).  Technically,
	 * there is no such thing as a string variable in C.  A string
	 * is really just a sequence (array) of characters.
	 *
	 * In this program, we will use a string variable to store my
	 * last name.
	 */
	char* last_name;


	/* Create a char (a single character value). For example,
	 * this could be used to store any single character in the
	 * alphabet.
	 *
	 * In this program, we will use a char variable to store my
	 * middle initial.
	 */
	char middle_initial;


	/* Create an integer (a whole number). Example values for
	 * an integer could be 0, 5, 384, -25 etc.  Note, that there
	 * is no decimal part to an integer.
	 *
	 * In this program, we will use an integer variable to store
	 * my age.
	 */
	int age;


	/* Create a float (a number with a fractional part). Example
	 * values could be 0.0, -5.6, 312.666 etc.
	 *
	 * In this program, we will use a float variable to store my
	 * hourly wage (in dollars and cents).
	 */
	float hourly_wage;


	/* Create a double (another number type with a fractional part).
	 * The difference between a double and a float is that doubles
	 * are designed to be bigger than floats (basically twice (double)
	 * as big).  Therefore a double is capable of storing a decimal
	 * value that has a significantly higher level of precision
	 * than a float.
	 *
	 * In this program, we will use a double variable to provide a
	 * measure of how much (compared to others) my intelligence
	 * may be of benefit to humanity.  We will want to use a double
	 * for this, because we know the value will be small.
	 */
	double effect_of_my_intelligence_on_humanity;


	/* ================================================================
	 * Now let's assign some values to the variables that we created
	 * ================================================================
	 */

	/* Use the 'last_name' variable to store my last name.
	 * Note the use of double quotes when dealing with strings.
	 */
	last_name = "Meyer";


	/* Use the 'middle_initial' variable to store my middle initial.
	 * Note the use of single quotes when dealing with chars.
	 */
	middle_initial = 'J';	/* For Jonathan	*/


	/* Use the 'age' variable to store my age */
	age = 30;


	/* Use the 'hourly_wage' variable to store my hourly wage
	 *(in dollars and cents).
	 */
	hourly_wage = 250.75;	/* Yah, I wish it were this much. */


	/* Use the 'effect_of_my_intelligence_on_humanity' variable to
	 * store a measure of how much my intelligence may be of benefit
	 * to humanity.  There is no scientific basis for the value I
	 * chose to use.  I do hope that my impact on humanity will
	 * indeed be positive however, regardless of how small it may
	 * turn out to be.
	 */
	effect_of_my_intelligence_on_humanity = 0.00000000000152;


    return 0;
}
Thanks for your input.

Eddie