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

#define PI 3.14159265

#define DEG2RAD(x) (x*PI/180)
#define RAD2DEG(x) (x*180/PI)

#define dt 0.00001
#define w 15
#define maxBoat 5.0
#define riverDrag 3.0

int main(void) {
    float t = 0;
    float x = 0, y = 0;
    float vx = -riverDrag, vy = maxBoat;
    float cx = 0, cy = 0;
    float theta = 0;

    for(t = 0;y<w;t+=dt) {
        x += (vx * dt);
        y += (vy * dt);

        theta = -atan((w - y) / x);
        vx = -riverDrag + maxBoat * cos(theta);
        vy = maxBoat * sin(theta);

        printf("%f,%f,%f\n", t,x, y);
    }

    return 0;
}