Result is only 5 decimal places even with long double (in c++)

Question

I wrote a c++ program to calculate pi using the infinite expansion for pi/4. I've used long double but still i get pi = 3.14158 . Where is the extra decimal chopped off. How to correct it? So is this is my code :

#include<iostream>
#include<math.h>
using namespace std;

int main(void)
{
    long double pi=1,si,i;

    for(i=1;i<100000;i++)
    {
        si = (pow(-1.0 ,i))/(2*i+1);
        pi += si;
    }

    pi*=4.0;
    cout<<"  "<< pi <<" \n ";
}

`std::cout` is chopping extra decimal. – Praveen Sep 04 '15 at 14:32 — Praveen, Sep 04 '15 at 14:32

score 1 · Answer 1 · edited May 23 '17 at 12:29

1

Your problem here is not the actual accuracy of the computed number, but in the formatting of your displayed output. Check this answer for details.

edited May 23 '17 at 12:29

Community

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answered Sep 04 '15 at 14:30

Logicrat

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Result is only 5 decimal places even with long double (in c++)

1 Answers1