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Join Date: Sep 2004
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Newbie Poster
I'm having problem writing code for a program that estimates the value of the mathematical constant e by using this formula e= 1 + 1/1! + 1/2!...
I just cant get this to work. Can someone please help
I just cant get this to work. Can someone please help
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Join Date: Feb 2002
Location: Lawn Guylen, NY
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Hmm ... start by writing a recurisve function to find the factorial of a number. There's a tutorial on recursion in either the C++ or the Computer Science section of this site - I forget which. You should also be able to find this function by doing a quick google search. Then just add 1/ to your factorial equation and it should do the trick 
Dani the Computer Science Gal
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Join Date: Sep 2004
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i guess it worked. I'm getting 0 as the answer. who knows.
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Newbie Poster
how do you get to calculae a power. is it pow(...)
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Join Date: Sep 2004
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>how do you get to calculae a power. is it pow(...)
Yes, that's one way.
Yes, that's one way.
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Join Date: Oct 2004
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Light Poster
I know that I'm breaking the rule not to make anybody's homwork.
But since the answer is so simple I can not help it to post a solution
K.
But since the answer is so simple I can not help it to post a solution
#include <iostream>
double fakt(int i)
{
if ( i == 1 )
return 1.0;
return fakt( i -1 ) * i;
}
int main() {
double e = 1.0;
for ( int i = 1; i < 4000; i++ ) {
e += 1.0 / fakt(i);
}
std::cout << " e = " << e << std::endl;
return 0;
} •
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Join Date: Sep 2004
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>for ( int i = 1; i < 4000; i++ ) {
>e += 1.0 / fakt(i);
Wow, I'm impressed if you can fit up to 3999! into a double. I just get undefined behavior when the limit of double is exceeded. :rolleyes:
>e += 1.0 / fakt(i);
Wow, I'm impressed if you can fit up to 3999! into a double. I just get undefined behavior when the limit of double is exceeded. :rolleyes:
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Join Date: Oct 2004
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@ Narue: you are right that 170! is the largest nr. that fits into a double.
but with my compiler the result is still correct because fact() simply returns inf for larger numbers then 170 and 1/inf returns 0.0 (btw I'm using gcc )
K.
but with my compiler the result is still correct because fact() simply returns inf for larger numbers then 170 and 1/inf returns 0.0 (btw I'm using gcc )
K.
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>but with my compiler the result is still correct
That's nice, but your code is still wrong even if the compiler that you use happens to interpret "undefined" as something intelligent.
That's nice, but your code is still wrong even if the compiler that you use happens to interpret "undefined" as something intelligent.
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Originally Posted by Narue
>but with my compiler the result is still correct
That's nice, but your code is still wrong even if the compiler that you use happens to interpret "undefined" as something intelligent.
K.
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