SourcePawn - player check - Lesson #3

#include <sourcemod>
#include <sdktools>

public OnPluginStart()
{
    RegAdminCmd("sm_sethp", sm_sethp, ADMFLAG_ROOT);
}

// sm_sethp <userid> <health>
public Action:sm_sethp(int client, int args)
{
    char userid[86]; // use userid from console 'status'
    char health[86];
    GetCmdArg(1, userid, sizeof(userid));
    GetCmdArg(2, health, sizeof(health));
    int target = GetClientOfUserId(StringToInt(userid));
    if(Client_IsValid(target) && IsPlayerAlive(target)) {
        SetEntityHealth(target, StringToInt(health));
    }
}

stock bool:Client_IsValid(client, bool:checkConnected=true)
{
    if (client > 4096) {
        client = EntRefToEntIndex(client);
    }

    if (client < 1 || client > MaxClients) {
        return false;
    }

    if (checkConnected && !IsClientConnected(client)) {
        return false;
    }

    return true;
}