a 11 vector2.c vector2 vec2plus(vector2 a, vector2 b){ a 13 vector2.c ret.x = a.x+b.x; a 14 vector2.c ret.y = a.y+b.y; a 18 vector2.c void vec2add(vector2* a, vector2* b){ a 19 vector2.c a->x = a->x+b->x; a 20 vector2.c a->y = a->y+b->y; a 23 vector2.c vector2 vec2minus(vector2 a, vector2 b){ a 25 vector2.c ret.x = a.x-b.x; a 26 vector2.c ret.y = a.y-b.y; a 30 vector2.c void vec2subtract(vector2* a, vector2* b){ a 31 vector2.c a->x = a->x-b->x; a 32 vector2.c a->y = a->y-b->y; a 35 vector2.c double vec2dot(vector2 a, vector2 b){ a 36 vector2.c return a.x*b.x+a.y*b.y; a 10 vector2.h vector2 vec2plus(vector2 a, vector2 b); a 11 vector2.h void vec2add(vector2* a, vector2* b); a 12 vector2.h vector2 vec2minus(vector2 a, vector2 b); a 13 vector2.h void vec2subtract(vector2* a, vector2* b); a 14 vector2.h double vec2dot(vector2 a, vector2 b);