#include <iostream>
#include <iomanip>
 
using namespace std;
 
double iterate(double x, double eps)
{
    x = x*x*x;
    double term = x/2, sum = x/2;
    for(int k = 3; abs(term) > eps; ++k)
        sum += (term *= x/k);
    return sum;
}
 
double recursion(double x, double eps, double term = 1, int k = 2)
{
    if (abs(term) < eps) return 0;
    term *= x*x*x/k;
    return term + recursion(x,eps,term,k+1);
}
 
int main()
{
    for(double x = 0; x < 2; x+= 0.2)
        cout << setw(10) << x << setw(15) << iterate(x,1e-8) << setw(15) << recursion(x,1e-8) << endl;
}
 

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