Marissa's Classes -- a transcription a Facebook chat with an extraordinarily clever girl who deserves a higher level of self-esteem and confidence.

Line.c

#include <stdlib.h>
#include "Line.h"

int getLength (Line *l) {
    return l->p2->x - l->p1->x;
}

Line* NewLine(void) {
    Line *l = (Line*) malloc (sizeof (Line));
    
    l->p1 = NewPoint();
    l->p2 = NewPoint();
    
    l->p1->x = 0;
    l->p2->x = 0;
    return l;
}

void KillLine(Line *l) {
    KillPoint(l->p1);
    KillPoint(l->p2);
    free(l);
}

Line.h

#include "Point.h"

typedef struct {
    Point *p1, *p2;
} Line;

int getLength (Line *l);
Line* NewLine(void);
void KillLine(Line *l);

main.c

#include <stdio.h>
#include <stdlib.h>
#include "Line.h" // Line.h already includes Point

int main(int argc, const char * argv[]) {
    printf("Hi. \n");
    
    Line *l = NewLine();
    l->p1->x = -1;
    l->p2->x = 1;
    
    printf("Length: %d\n", getLength(l));
    
    return 0;
}

Point.c

#include "Point.h"

#include <stdlib.h>

int getDistance(Point *p) {
    return p->x;
}

Point * NewPoint(void) {
    Point *p = (Point *) malloc (sizeof (Point));
    p->x = 0;
    return p;
}

void KillPoint(Point *p) {
    free(p);
}

Point.h

    // Marissa wrote all of this.
    // Copied and pasted right from Facebook chat.

typedef struct {
    int x;
} Point;

int getDistance(Point *p);
Point* NewPoint(void);
void KillPoint(Point *p);