Visualize lines in C terminal given two points

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

const int MIN_X = -40, MIN_Y = -12,
          MAX_X = 40, MAX_Y = 12;

typedef struct {
    int x;
    int y;
} point;

typedef struct {
    point a;
    point b;
    double rico;
    double m;
} line;

void plot_grid();
void plot_line(line *k);
int get_highest(int x, int y);
void calc_line(line *k);

int main(int argc, char** argv)
{
    //plot_grid();

    line x = {
        { -25, -7 },
        { 30, 5 },
        0.0,
        0.0
    };

    plot_line(&x);

    return 0;
}

void calc_line(line *k)
{
    //line <=> y = (rico)*x + m
    int highest = get_highest(k->a.y, k->b.y);
    double dY, dX;

    //set dY, dX;
    if(highest == k->b.y)
    {
        //verschil in Y en X
        dY = k->b.y - k->a.y;
        dX = k->b.x - k->a.x;
    }
    else
    {
        //verschil in Y en X
        dY = k->a.y - k->b.y;
        dX = k->a.x - k->b.x;
    }

    if(dX != 0)
        k->rico = dY / dX;

    double temp = k->rico * k->b.x;

    if(temp != 0)
    {
        // y = (rico)x + m => m = y/(rico)x
        k->m = k->b.y / temp;
    }

    printf("m = %f, rico = %f\n\n", k->m, k->rico);
}

void plot_line(line *k)
{
    int i, j;

    calc_line(k);


    printf("m = %f, rico = %f\n\n", k->m, k->rico);

    for(i = MIN_Y; i < MAX_Y; i++)
    {
        for(j = MIN_X; j < MAX_X; j++)
        {
            int temp = (int)floor(k->rico * j + k->m) * -1;

            if(temp != i)
            {
                if(j != 0)
                {
                    if(i != 0)
                        printf(" ");
                    else
                        printf("-");
                }
                else
                {
                    if(i != 0)
                        printf("|");
                    else
                        printf("+");
                }
            }
            else
            {
                printf("*");
            }
        }
    }
}

int get_highest(int x, int y)
{
    int k = 0;

    if(y > x)
        k = y;
    else
        k = x;

    return k;
}

void plot_grid()
{
    int x, y;

    for(y = MIN_Y; y < MAX_Y; y++)
    {
        for(x = MIN_X; x < MAX_X; x++)
        {
            if(x != 0)
            {
                if(y != 0)
                    printf(" ");
                else
                    printf("-");
            }
            else
            {
                if(y != 0)
                    printf("|");
                else
                    printf("+");
            }
        }
    }
}