CORDIC method

#include<stdio.h>
#include <math.h>

#define PI_OVER_6 0.523598776

double mycos(double theta, int n) {
    double x, y, z;
    // compute k
    double k = 1;
    for (int i = 0; i < n; ++i) {
        k *= sqrt(1 + pow(2, -2 * i));
    }

    x = 1/k;
    y = 0;
    z = theta;
    double nextX, nextY, nextZ;
    double alpha;
    double measuredError = 0;

    for (int i = 0; i < n; ++i) {
        alpha = atan(pow(2, -i));
        measuredError = x - cos(PI_OVER_6);

        printf("x(%d) = %lf\n", i, x);
        printf("y(%d) = %lf\n", i, y);
        printf("z(%d) = %lf\n", i, z);
        printf("alpha(%d) = %lf\n", i, alpha);

        printf("Measured error: %lf\n", measuredError);
        if (z >= 0) {
            nextX = x - (pow(2, -i) * y);
            nextY = y + (pow(2, -i) * x);
            nextZ = z - atan(pow(2, -i));
        } else {
            nextX = x + (pow(2, -i) * y);
            nextY = y - (pow(2, -i) * x);
            nextZ = z + atan(pow(2, -i));
        }

        x = nextX;
        y = nextY;
        z = nextZ;
    }
    return nextX;
}

int main() {
    double piOver6 = 0.523598776;

    double theta = piOver6, result;
    int n = 0;
    while(1) {
        //printf("cos(theta) = ?; type in theta: \n");
        //scanf("%lf", &theta);
        printf("type in n (number of iterations): \n");
        scanf("%d", &n);

        printf("RESULT: %lf\n\n", mycos(theta, n));
    }
    return 0;
}