[Konstantinos]

By the way, set only a variable of rank and set it from 1 to 4. It is not needed to create 4 different variables for that.

pawn Код:

COMMAND:finvite( playerid, params[ ] )
{
    if( !sLeader( playerid ) ) return SendClientMessage( playerid, 0xFF0000FF, "Only the SA-PD Leader can use this command!" );
    new
        toplayerid, // the player we want to make SA-PD
        rank
    ; // extracting player's ID and rank from params
    if( sscanf( params, "ri", toplayerid, rank ) ) return SendClientMessage( playerid, 0xFFFFFFFF, "Usage: /finvite <playerid> <rank>" );
    if( toplayerid == INVALID_PLAYER_ID ) return SendClientMessage( playerid, 0xFF0000FF, "That player is not connected" );
    if( rank < 1 || rank > 4 ) return SendClientMessage( playerid, 0xFF0000FF, "The rank value must be between 1 and 4." );
    new
        message[ 40 ]
    ;
    format(message, sizeof(message), "You were set rank %i By the SA-PD Leader.!", rank);
    SendClientMessage(toplayerid, 0x00FF00FF, message);
    // Set your rank here!
    return 1;
}