You'll have to tweak your algorithm a bit to calculate the angle - currently you only record the absolute difference in position, but you need the relative difference (i.e. can be positive or negative depending on positioning).

int dx = T.X - S.X; // difference in position
int dy = T.Y - S.Y;

if (dx > MapX / 2) // if distance is bigger than half map width, then looping must be closer
    dx = (dx - (MapX / 2)) * -1; // reduce distance by half map width, reverse 
else if (dx < -MapX / 2) // handle the case that dx is negative
    dx = (dx + (MapX / 2)) * -1;

//Do the same for dy
if (dy > MapY / 2)
    dy = (dy - (MapY / 2)) * -1;
else if (dy < -MapY / 2)
    dy = (dy + (MapY / 2)) * -1;

double dist = sqrt(dy*dy+dx*dx); // same as before
double angle = atan2(dy,dx) * 180 / PI; // provides angle in degrees

You'll have to tweak your algorithm a bit to calculate the angle - currently you only record the absolute difference in position, but you need the relative difference (i.e. can be positive or negative depending on positioning).

int dx = T.X - S.X; // difference in position
int dy = T.Y - S.Y;

if (dx > MapX / 2) // if distance is bigger than half map width, then looping must be closer
    dx = (dx - MapX) * -1; // reduce distance by map width, reverse 
else if (dx < -MapX / 2) // handle the case that dx is negative
    dx = (dx + MapX) * -1;

//Do the same for dy
if (dy > MapY / 2)
    dy = (dy - MapY) * -1;
else if (dy < -MapY / 2)
    dy = (dy + MapY) * -1;

double dist = sqrt(dy*dy+dx*dx); // same as before
double angle = atan2(dy,dx) * 180 / PI; // provides angle in degrees