58 void VCross(vector *a, vector *b, vector *c) {  in VCross()  argument
59     c->x = (a->y * b->z) - (a->z * b->y);  in VCross()
60     c->y = (a->z * b->x) - (a->x * b->z);  in VCross()
61     c->z = (a->x * b->y) - (a->y * b->x);  in VCross()
79 void VAdd(vector *a, vector *b, vector *c) {  in VAdd()  argument
80     c->x = (a->x + b->x);  in VAdd()
81     c->y = (a->y + b->y);  in VAdd()
82     c->z = (a->z + b->z);  in VAdd()
85 void VSub(vector *a, vector *b, vector *c) {  in VSub()  argument
86     c->x = (a->x - b->x);  in VSub()
87     c->y = (a->y - b->y);  in VSub()
88     c->z = (a->z - b->z);  in VSub()