Ever heard of casting?

[ArchimaX]

This is an excerpt from some sample code provided in the documentation for an EFT interface

decimal divider;
// we need 10^18, but Math.Pow does not support decimal
// types and decimal does not provide a power function
divider = 10*10*10;
divider = Decimal.Multiply(divider,10*10*10*10*10);
divider = Decimal.Multiply(divider,10*10*10*10*10);
divider = Decimal.Multiply(divider,10*10*10*10*10);

Blows my mind :-)

[OriginalGriff]

Never mind casting - at least he didn't use a loop:

        decimal tenE18 = 1;
        for (int i = 0; i < 18; i++)
            {
            tenE18 \*= 10;
            }

Still, I think I will stick to the old-fashioned, boring way:

        decimal d = 1E18M;

[edit]Got the number of zeros wrong, didn't I? Oops.[/edit]

You should never use standby on an elephant. It always crashes when you lift the ears. - Mark Wallace C/C++ (I dont see a huge difference between them, and the 'benefits' of C++ are questionable, who needs inheritance when you have copy and paste) - fat_boy

modified on Wednesday, March 3, 2010 11:21 AM

[chevu]

well you can do something that save time and processing time, try this decimal res = 10; decimal rem = 1; int pow = 18; while(pow > 0) { res *= res; rem *= (pow%2)? 1:10; pow /= 2; } res *= rem;

[Stanciu Vlad]

OriginalGriff wrote:

Still, I think I will stick to the old-fashioned, boring way:

decimal d = 10E18M;

//
// TODO: Check the number is 10^18
//

decimal bigNumber = 1000000000000000000M;

This makes the old-fashioned way more exciting :laugh:

I have no smart signature yet...

[johannesnestler]

run your code -> how many digits do you count? ;P

[johannesnestler]

:wtf: test your code - it saves processing time, but raises debug time - if you are able to compile it ;P

[OriginalGriff]

I did - and checked they gave the same results before I posted it. ;P

You should never use standby on an elephant. It always crashes when you lift the ears. - Mark Wallace C/C++ (I dont see a huge difference between them, and the 'benefits' of C++ are questionable, who needs inheritance when you have copy and paste) - fat_boy

[Luc Pattyn]

that is completely wrong in many ways. did you try a simple example, say pow=1? :~

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

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I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.

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[johannesnestler]

:omg: lol - same results... Check it:

using System;

namespace DecimalTest
{
class Program
{
static void Main(string[] args)
{
decimal divider;
// we need 10^18, but Math.Pow does not support decimal
// types and decimal does not provide a power function
divider = 10*10*10;
divider = Decimal.Multiply(divider,10*10*10*10*10);
divider = Decimal.Multiply(divider,10*10*10*10*10);
divider = Decimal.Multiply(divider,10*10*10*10*10);
Console.WriteLine(divider);

        decimal tenE18 = 10;
        for (int i = 0; i < 18; i++)
            tenE18 \*= 10;
        Console.WriteLine(tenE18);
        Console.WriteLine(10E18M);

        Console.WriteLine(String.Format("{0:N}", Math.Pow(10d, 18d)));
     
        Console.ReadKey();
    }
}

}

who invented those nasty zero!?! :laugh:

[OriginalGriff]

Yeah, I checked my results matched! :-O I didn't check his! Oops.

You should never use standby on an elephant. It always crashes when you lift the ears. - Mark Wallace C/C++ (I dont see a huge difference between them, and the 'benefits' of C++ are questionable, who needs inheritance when you have copy and paste) - fat_boy

[johannesnestler]

using System;

namespace DecimalTest
{
class Program
{
static void Main(string[] args)
{
decimal bigNumber = 1000000000000000000M;
decimal bigNumber2 = 10E18M;

        Console.WriteLine("Is {0} the same as {1}?", bigNumber, bigNumber2);
        if (bigNumber == bigNumber2)
            Console.WriteLine("WTF???");
        else
            Console.WriteLine("No - Maths saved!");
     
        Console.ReadKey();
    }
}

}

[johannesnestler]

yea - it was even hard for me to check his crazy code - lol. There is some resistence to execute such a thing - :)

[Luc Pattyn]

castling? sure, I do it every day. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

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I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.

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[Lost User]

Is that an attempt at binary exponentiation?

[chevu]

it might have a syntax error but you can do it this way.. you can refer algorithm by corman... n compare to given algo for (int i = 0; i < 18; i++) { tenE18 *= 10; } this one will run for 18times.. for debuging also you have to go through this loop 18 times... then how can you say algo i gave takes more time to debug.. complexity of given algo is O(n) and complexity of algo i gave is O(lg(n))....

modified on Wednesday, March 3, 2010 10:37 PM

[Luc Pattyn]

chevu wrote:

how can you say algo i gave takes more time to debug.. complexity of given algo is O(n)

O(n) and O(lg(n)) apply to execution time, not debugging time. There are no formulas for debugging time; it depends on number of statements, decision points, readability of code, and initial number of bugs. Your code has more than 5 bugs, it will take you lots of time to find all of them. I suggest you try and fix and run it until the result is correct. :|

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

---

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.

---

[chevu]

sorry i messed up with code... This one is correct code

decimal res = 10;
decimal multi = 10;
decimal rem = 1;
int pow = 18;//For pow 0 you can directly return with 0

while(pow > 1)
{
res *= res;
rem *= (pow%2)? multi:1;
pow /= 2;
}
res *= rem;

[Luc Pattyn]

chevu wrote:

This one is correct code

wrong again: 1. the result for pow=18 is wrong. 2. pow=5 and pow=6 give the same result??? I think you have abundantly proven now that your code has high debugging complexity. :(

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

---

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.

---

[chevu]

sorry dude... i had really forget to check till 18... coz of odd even cases that code will fail... I knw you people are getting irritated by now, but you can check this code

double pow(long long a, long long b)
{
if(b == 0)
return 1.0;
else if(b == 1)
return a;
else if(b%2 == 0)
return pow(a*a,b/2);
else
return a* pow(a*a,b/2);
}

i have tested this code upto long long limits...

[Stanciu Vlad]

Recursive functions brings color in life :-D

I have no smart signature yet...