程序代码：

#include<stdio.h>
int main()
{
    double g, x0, y0, vx, vy, ts, te, dt;
    double x, y, t;
    g = 9.8;
    x0 = 0;
    y0 = 0;
    vx = 20;
    vy = 20;
    ts = 0;
    te = 5;
    dt = 0.1;

    for(t = ts; t <= te; t += dt)
    {
        x = vx * t + x0;
        y = vy * t - g / 2 * t * t + y0;
        printf("%f,%f\n", x, y);
    }
    return 0;
}