18 lines
239 B
C++
18 lines
239 B
C++
#include<iostream>
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#include<cmath>
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using namespace std;
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int main()
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{
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long double pi4=0;
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long long n=1,j=1;
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do
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{
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if(j%2==1) pi4=pi4+1.0/n;
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else pi4=pi4-1.0/n;
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n+=2;
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j++;
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}while(1.0/n>=0.000001);
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cout<<pi4*4.0;
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while(true);
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}
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