27 lines
606 B
C++
27 lines
606 B
C++
/* 求π.cpp */
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#include <iostream>
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using namespace std;
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double arctan(double x);
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int main(int argc, char const *argv[]) {
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double a = 16.0 * arctan(1.0 / 5.0);
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double b = 4.0 * arctan(1.0 / 239.0);
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double pi = a - b;
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cout << pi << endl;
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return 0;
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}
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double arctan(double x) {
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double head = x;
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int tail = 1;
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double art = 0;
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while (double(head / tail) > 1e-15) {
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art = (tail % 4 == 1) ? art + head / tail : art - head / tail;
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head *= x * x;
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tail += 2;
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cout << "---------------" << endl;
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cout << tail << endl;
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cout << "---------------" << endl;
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}
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return art;
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}
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