public Float:GetDistanceBetweenPlayers(p1,p2)
{    
    new Float:x1,Float:y1,Float:z1,Float:x2,Float:y2,Float:z2;    
     if(!IsPlayerConnected(p1) || !IsPlayerConnected(p2))
     {    
     return -1.00;    
     }    
    GetPlayerPos(p1,x1,y1,z1);    
    GetPlayerPos(p2,x2,y2,z2);    
return floatsqroot(floatpower(floatabs(floatsub(x2,x1)),2)+floatpower(floatabs(floatsub(y2,y1)),2)+floatpower(floatabs(floatsub(z2,z1)),2));    
}

forward Float:GetDistanceBetweenPlayers(playerid1,playerid2);
stock Float:GetDistanceBetweenPlayers(playerid1,playerid2)
{
     new Float:x1, Float:y1, Float:z1, Float:x2, Float:y2, Float:z2;
     if(!IsPlayerConnected(playerid1) || !IsPlayerConnected(playerid2)) return -1.00;
     GetPlayerPos(playerid1, x1, y1, z1);
     GetPlayerPos(playerid2, x2, y2, z2);
     return floatsqroot((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1) + (z2 - z1) * (z2 - z1));
}