how to get distance between me and vehicles near me ?

here code

for (int i = 0; i base.matrix[4 * 3];

player_pos.x = f_pos[0];

player_pos.y = f_pos[1];

player_pos.z = f_pos[2];

CalcScreenCoors(&player_pos, &screenposs);

float * f_poss = &vehicle->base.matrix[4 * 3];

vehicle_pos.x = f_poss[0];

vehicle_pos.y = f_poss[1];

vehicle_pos.z = f_poss[2];

CalcScreenCoors(&vehicle_pos, &vscreenposs);

thanks for help !