```
// Cubic conversion of Borwein's Algorithm
// Each iteration converges
// cubically against 1/pi;
// that is, each iteration
// approximately triples the
// number of correct digits.
// Program written by ROBO_HEN5000
// Algorithm complements of Wikipedia.
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
float a;
double pi;
double s;
double r;
double k;
int iterations;
int repetitions = 0;
cout << "How many iterations of the equation would you like? \n";
cout << "The first iteration yields 3.14.\nEach iteration triples the number of correct digits.";
cin >> iterations;
cout << "\nCalculating Pi...\n";
s = (sqrt(3)-1)/2;
a = 1.0/3;
while (iterations >= repetitions)
{
r = 3/(1+2*pow((1-pow(s,3.0)),(1/3)));
s = (r-1)/2;
a = pow(r,2)*a-pow(3,k)*(pow(r,2)-1);
repetitions++;
};
pi = 1/a;
cout << "Pi = " << pi;
return 0;
}
```

please correct my mistakes. i am tired