Use snippet showroom.

See, Put it first:

[pawn]new IsCop[MAX_PLAYERS];[/pawn]


Now in the OnPlayerSpawn event:

[pawn]public OnPlayerSpawn(playerid,classid)
{
        new IsCop[MAX_PLAYERS];
        IsCop[playerid]=1;
        new gPlayers[MAX_PLAYERS][MAX_PLAYER_NAME+1];
        new string[256];
   GetPlayerName(playerid,gPlayers[playerid],MAX_PLAYER_NAME);
        format(string,sizeof(string),"%s has spawned as cop.",gPlayers[playerid]);
        SendClientMessageToAll(COLOR_YELLOW,);
   return 1;
}[/pawn]

Wave...

Brief Explanation:

                             The computer obviously needs machine language to understand what we are saying. The vcmp server scripts need machine code/language to understand that what functions we are putting! But we type these things in our language. So the pawno compiler is a software or you can say a program, that translates our language to machine's one! Now the server will only see the mode.amx file. Even if you delete the mode.pwn file then the server and the script will still run.
understand? when you have made changes to the script in mode.pwn then you will have to compile it! so that the server could read and understand the language/functions/commands etc...

[Specially made easy for easily understanding]