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

#ifndef __VEC_H__
#define __VEC_H__

#define NMAT	4
typedef struct _vector {
    double x, y, z;
} Vector;
typedef struct _line {
    Vector *start, *end;
} Line;
void vadd(Vector *a, Vector *b, Vector *c);
void vsub(Vector *a, Vector *b, Vector *c);
double dotprod(Vector *a, Vector *b);
void crossprod(Vector *a, Vector *b, Vector *c);
void smul(double s, Vector *a, Vector *b);
void vnorm(Vector *src, Vector *dst);
void vmul(double m[NMAT][NMAT], Vector *a, Vector *b);
void mmult(double a[NMAT][NMAT], double b[NMAT][NMAT], double c[NMAT][NMAT]);
void getmatrix(double m[NMAT][NMAT],Vector *p,Vector *v);
void project(Vector *a, double d, Vector *ans);
void printvec(Vector *v);
void printmatrix(double m[NMAT][NMAT]);
#endif