// PROGRAM free_fall

#include "TrueBASIC.h"
int main();
void initial();
void Euler();
void print_table();

int nshow;
double a;
double dt;
double g;
double t;
double v;
double y;

int main()
{
    int counter;

    initial();
    print_table();
    counter = 0;
    while(y >= 0)
    {
        Euler();
        if((++counter % nshow) == 0)
            print_table();
    }
    print_table();

    GWquit();
    return 0;
}

void initial()
{
    t = 0;
    y = 10;
    v = 0;
    g = 9.8;
    a = -g;
    dt = 0.01;
}

void Euler()
{
    y += v*dt;
    a = -g;
    v += a*dt;
    t += dt;
}

void print_table()
{
    char Stmp1_[_LBUFF_];

    if(t == 0)
    {
        printf("number of time steps between output = ");
        fgets(Stmp1_, _LBUFF_, stdin);
        sscanf(Stmp1_, "%d", &nshow);
        printf("\n    time (s)        y (m) velocity (m/s) accel (m/s*s)\n\n");
    }
    printf("%12f %12f %12f %12f\n", t, y, v, a);
}