MacLin : A technologic revolution

After having created the code for my last post, I began to search a way to improve it. In the version previously posted, I used a “double” and at the 1024th loop my Macbook is showing me an “inf” instead of a numerical value… which means that I have overflowed the value of a double. I then tried different thing, my goal was to get the “infinite” as far as possible. After some reflexion I decided to use the biggest value for Integer Unit and then Floating Point Unit. Using an “unsigned long long” I realized that the value would never become “infinite” but would stay constant at “18446744073709551615″ after the 63th execution loop. Using a “long double” I’ve been able to get the “infinite” to appear only after the 16383th execution loop with a value of “6E+4931″.

This bring me the interest of knowing the limits for the different types on my Macbook Pro. I search a bit on the net and found a simple piece of C code from “Alberto Bertogli” that simply display all the informations I was interested in.

max value of char: 127
min value of char: -128
max value of int: 2147483647
min value of int: -2147483648
max value of long: 2147483647
min value of long: -2147483648
min value of long long: -9223372036854775808
max value of long long: 9223372036854775807
max value of unsigned long long: 18446744073709551615
max value of signed char: 127
min value of signed char: -128
max value of short: 32767
min value of short: -32768
max value of unsigned char: 255
max value of unsigned int: 4294967295
max value of unsigned long 4294967295
max value of unsigned short: 65535
max value of double: 1.797693e+308
min value of double: 2.225074e-308
max value of double 10 exp: 308
min value of double 10 exp: -307
max value of long double: 1.18973e+4932
min value of long double: 3.3621e-4932
max value of long double 10 exp: 4932
min value of long double 10 exp: -4931
max value of float: 3.40282e+38
min value of float: 1.17549e-38
max value of float 10 exp: 38
min value of float 10 exp: -37
——————————————————-
sizeof char: 1
sizeof short: 2
sizeof int: 4
sizeof long: 4
sizeof long long: 8
sizeof double: 8
sizeof long double: 16
sizeof float: 4
——————————————————-
sizeof off_t: 8
sizeof size_t: 4
sizeof ssize_t: 4
name max: 255
path max: 1024

By executing this code I realized that the previously obtained “18446744073709551615″ was the maximum value of an “unsigned long long”. I then though that “6E+4931″ would be the maximum value of a “long double” but I was wrong, the limits for a “long double” is “10^4932″ and it’s easy to understand why I get the “infinite” after getting “6E+4931″ because by doing a multiplication by 2 and adding one (thats what the love code do) you get over the limit of a “long double” so … you get the “infinite”.

/*
 * limits.c
 * Alberto Bertogli (albertogli@telpin.com.ar)
 * 22/Oct/2002
 *
 * Shows the limits of data types.
 *
 * Try compiling it with "gcc -std=c99 limits.c -o limits"
 */

#include <stdio.h>
#include <limits.h>
#include <stdint.h>
#include <float.h>
#include <fcntl.h>
#include <sys/param.h>	/* for PATH_MAX and NAME_MAX */

int main(void) {
	printf("max value of char: %d\n", CHAR_MAX);
	printf("min value of char: %d\n", CHAR_MIN);

	printf("max value of int: %d\n", INT_MAX);
	printf("min value of int: %d\n", INT_MIN);

	printf("max value of long: %ld\n", LONG_MAX);
	printf("min value of long: %ld\n", LONG_MIN);

#ifdef LLONG_MIN
	printf("min value of long long: %lld\n", LLONG_MIN);
	printf("max value of long long: %lld\n", LLONG_MAX);
	printf("max value of unsigned long long: %llu\n", ULLONG_MAX);
#else
	printf("long long limits unavailable (compile with -std=c99)\n");
#endif

	printf("max value of signed char: %d\n", SCHAR_MAX);
	printf("min value of signed char: %d\n", SCHAR_MIN);

	printf("max value of short: %d\n", SHRT_MAX);
	printf("min value of short: %d\n", SHRT_MIN);

	printf("max value of unsigned char: %u\n", UCHAR_MAX);
	printf("max value of unsigned int: %u\n", UINT_MAX);
	printf("max value of unsigned long %lu\n", ULONG_MAX);
	printf("max value of unsigned short: %u\n", USHRT_MAX);

	printf("max value of double: %e\n", DBL_MAX);
	printf("min value of double: %e\n", DBL_MIN);

	printf("max value of double 10 exp: %i\n", DBL_MAX_10_EXP);
	printf("min value of double 10 exp: %i\n", DBL_MIN_10_EXP);

	printf("max value of long double: %Lg\n", LDBL_MAX);
	printf("min value of long double: %Lg\n", LDBL_MIN);

	printf("max value of long double 10 exp: %i\n", LDBL_MAX_10_EXP);
	printf("min value of long double 10 exp: %i\n", LDBL_MIN_10_EXP);

	printf("max value of float: %g\n", FLT_MAX);
	printf("min value of float: %g\n", FLT_MIN);

	printf("max value of float 10 exp: %i\n", FLT_MAX_10_EXP);
	printf("min value of float 10 exp: %i\n", FLT_MIN_10_EXP);

	printf("-------------------------------------------------------\n");

	printf("sizeof char: %d\n", sizeof(char));
	printf("sizeof short: %d\n", sizeof(short));
	printf("sizeof int: %d\n", sizeof(int));
	printf("sizeof long: %d\n", sizeof(long));
	printf("sizeof long long: %d\n", sizeof(long long));
	printf("sizeof double: %d\n", sizeof(double));
	printf("sizeof long double: %d\n", sizeof(long double));
	printf("sizeof float: %d\n", sizeof(float));

	printf("-------------------------------------------------------\n");

	printf("sizeof off_t: %d\n", sizeof(off_t));
	printf("sizeof size_t: %d\n", sizeof(size_t));
	printf("sizeof ssize_t: %d\n", sizeof(ssize_t));
	printf("name max: %d\n", NAME_MAX);
	printf("path max: %d\n", PATH_MAX);

	return 0;

}

#include <iostream>
#define END_OF_LIFE 74*365    // 74 years in days
							  // Accordingly to the Deathclock I'll die at 74

int main (int argc, char * const argv[]) {

	int dayPassedTogether;
	long double love = 1;

	for(dayPassedTogether = 1; dayPassedTogether <= END_OF_LIFE; dayPassedTogether++) {
		printf("Each day my love for you is incremented : %0.LE\n",love);
		love += love;
		love++;
	}

    return 0;
}

With all the Valentine’s Day and love floating around me these day, I felt like expressing it in all my geekiness. So, tonight I wrote a simple C++ code to express how I feel about a very special someone.

Damn theme … I don’t know how to make code appear correctly … I mean with proper indentation!

EDIT: Haaaa… I found a very nice wordpress plugin to help me

#include <iostream>

#define END_OF_LIFE 80*365    // 80 years in days

int main (int argc, char * const argv[]) {

	int dayPassedTogether;
	double love = 1;

	for(dayPassedTogether = 1; dayPassedTogether <= END_OF_LIFE; dayPassedTogether++) {
		printf("Each day my love for you is incremented : %0.f\n",love);
		love += love;
		love++;
	}

    return 0;
}

Before starting to blog about today’s topic, I would like to assure you that the MythTV setup part will come as soon as I get time to make some good screenshot and all. I’ll also look to enter inside MythTV development soon… when the mid-term exams and homework will be done.

Today’s topic is about a funny website that my friend François Proulx shown me a couple of week ago. The site is in fact a “Computer Science Papers Generator” it’s really funny when you try it. But what is much more funny is when you read on the website and see that a paper generated by this system have been accepted in the WMSCI 2005 conference… a proof that sometimes selection committee are not looking to the contents of a submited document but to the format.

Anyway, try it, enter some friend names and you will laught. Sometimes you can even find similarity with some University Teacher in the use of BuzzWord

Well it’s a long time since I write here, I’m sorry about that. I prefer not to write instead of saying something not interesting. By the way I wish a lot of persons will come to the biggest party at ÉTS (my engineering school) so here is the flyer to give you more information. But I must warn you that it’s really the best school party in Montréal !

If you’re a lady, bring another one and you have a 2/1 ticket!

September 14 !!!