怎么用c++完成呢，求解答

#include<iostream>
#include<cmath>
using namespace std;
int main(void) {
    float r, x0 = 0;
    float x1 = cos(x0);
    while (fabs(x0 - x1) > 0.000001) {
        x0 = x1;
        x1 = cos(x0);
    }
    cout << x1;
    return 0;
}