--- Log opened Fri Feb 09 16:12:05 2018
16:12 -!- Nuclear [nuclear@mutantstargoat.com] has joined #megalikourasi
16:12 -!- Irssi: #megalikourasi: Total of 1 nicks [1 ops, 0 halfops, 0 voices, 0 normal]
16:12 -!- Irssi: Join to #megalikourasi was synced in 0 secs
16:13 -!- XXX-1244139498 [~george@wifi-232-195.wireless.ntua.gr] has joined #megalikourasi
16:13 <@Nuclear> geiaaa
16:13 < XXX-1244139498> geiaaaa 
16:13 < XXX-1244139498> vasika den allaksa nickname, oti pire aytomata 
16:13 <@Nuclear> sou allakse to nickname se XXX epidi to george kapoios to exei kanei register
16:13 -!- XXX-1244139498 is now known as gkops
16:14 <@Nuclear> opos ego exo to nuclear, an pas na mpeis san nuclear kai den baleis ton kodiko tou nickname, meta apo ligo tha sto allaksei se XXX
16:14 <@Nuclear> so anyway, pio aneta edo... pou les ta paradeigmata me to operator overloading pou sou eixa dosei itan os eksis:
16:14 <@Nuclear> prosthesi complex kai complex:
16:14 <@Nuclear> ComplexNum operator+(ComplexNum a, ComplexNum b)
16:14 <@Nuclear> { return ComplexNum(a.re + b.re, a.im + b.im);
16:15 <@Nuclear> }
16:15 <@Nuclear> pollaplasiazmos complex kai float:
16:15 <@Nuclear> ComplexNum operator *(ComplexNum c, float s)
16:15 <@Nuclear> {
16:15 <@Nuclear>     return ComplexNum(c.re * s, c.im * s);
16:15 <@Nuclear> }
16:15 <@Nuclear> (etsi doulevei to a * 2.0)
16:16 <@Nuclear> kai gia na doulevoun kai ta dyo, prepei na diloseis KAI to operator*(float, ComplexNum)
16:16 <@Nuclear> opote:
16:16 <@Nuclear> ComplexNum operator *(float s, ComplexNum c)
16:16 <@Nuclear> {
16:16 <@Nuclear>     return ComplexNum(c.re * s, c.im * s);
16:16 <@Nuclear> }
16:16 <@Nuclear> tora ta vlepeis sosta elpizo
16:17 < gkops> nai nai twra ola komple
16:17 -!- Nuclear changed the topic of #megalikourasi to: I kourasi einai megali
16:17 <@Nuclear> opote tora me ayta mporeis eykola na allakseis ton kodika tou fractal na xrisimopoiei operators pistevo, exeis kamia aporia ?
16:18 < gkops> oxi nomizw oti mporw na to kanw
16:18 < gkops> afoy perasame ton skopelo tis arxis 
16:18 < gkops> mi lew kai megales kouventes vevaia xaxa
16:18 <@Nuclear> loipon akou kai kati allo pou den sto exo pei mexri stigmis alla einai xrisimo
16:19 <@Nuclear> epitides den sto eipa mexri tora gia na min se mperdepso
16:19 <@Nuclear> tha thymasai oti otan pername parametro se mia synartisi, i parametros antigrafetai kai i synartisi pairnei diko tis antigrafo, sosta?
16:21 < gkops> nai nai 
16:21 <@Nuclear> otan ayti i parametros einai ena int, i ena float, ayto den einai provlima, giati i antigrafi tou einai ena assignment se mia alli thesi mnimis
16:21 <@Nuclear> pou ginetai me ena machine instruction
16:21 <@Nuclear> poly grigoro
16:21 <@Nuclear> alla otan pernas oloklira objects apo kapoia class san parametro, ola ta pedia tis classis prepei na antigrafoun
16:21 <@Nuclear> stin periptosi tou ComplexNum den einai provlima episis, giati exei mono 2 floats mesa
16:22 <@Nuclear> alla se megalytera antikeimena, den einai kali idea na antigrafeis ena tono dedomena apla gia na to xrisimopoiiseis san *input* se synartisi
16:22 <@Nuclear> px mesa stin add_complex (i sto operator+)  to a kai to b den to peirazeis pote
16:22 <@Nuclear> apla diabazeis ti timi exoun ta re kai im tous
16:22 <@Nuclear> den xreiazetai na kaneis olokliro antigrafo tou kathe object gia na deis tis times aytes
16:22 <@Nuclear> einai perito
16:23 <@Nuclear> tha itan protimotero, kapos na pareis access sta original pedia tou original antikeimenou pou pernas san A parametro i B parametro
16:23 <@Nuclear> anti na to antigrapseis kai na diabaseis apo to antigrafo
16:23 <@Nuclear> symfoneis / akolouytheis to skeptiko mou ?
16:24 < gkops> nai mexri edw kala 
16:24 <@Nuclear> oraia... an egrafes tin idia synartisi stin C pos tha mporouses na to kaneis ayto?
16:24 <@Nuclear> (tin add_complex)
16:24 <@Nuclear> tha mporouses anti na peraseis san parametro ComplexNum a
16:24 <@Nuclear> (pou tha ginei antigrafo tou structure (stin C) i tis class (stin C++)....
16:24 <@Nuclear> na peraseis pointer sto original antikeimeno
16:25 <@Nuclear> diladi an grapseis tin synartisi anti gia:
16:25 <@Nuclear> ComplexNum add_complex(ComplexNum a, ComplexNum b)
16:25 <@Nuclear> na tin grapseis san ComplexNum add_complex(ComplexNum *a, ComplexNum *b)
16:26 <@Nuclear> me ayto ton tropo den antigrafetai to object, giati den pernas to object, pernas ena pointer, opote antigrafetai to pointer mono (me ena machine instruction) kai mporeis na xrisimopoiiseis ayto to pointer kanontas to dereference gia na *deis* ta periexomena tou arxikou antikeimenou
16:26 <@Nuclear> Ayto tha to xrisimopoiouses ap'ekso os:
16:26 <@Nuclear> ComplexNum a, b, c;
16:26 <@Nuclear> c = add_complex(&a, &b);
16:26 <@Nuclear> giati einai pointers, opote thes ti dieythinsi san parametro
16:26 <@Nuclear> katanoito os edo ?
16:27 <@Nuclear> kai fysika tha allaze kai i idia i add_complex, giati prepei na kanei dereferences
16:27 <@Nuclear> tha ginotan:
16:27 <@Nuclear> ComplexNum add_complex(ComplexNum *a, ComplexNum *b)
16:27 <@Nuclear> {
16:27 < gkops> nai nai sto thewritiko kommati katanoito 
16:27 < gkops> katse na dw kai to prkatiko twra 
16:27 <@Nuclear>     return ComplexNum(a->re + b->re, a->im + b->im);
16:27 <@Nuclear> }
16:27 <@Nuclear> ok ?
16:28 < gkops> ok nai 
16:28 <@Nuclear> ayto einai kati pou tha mporouses na to kaneis kai stin C kai stin C++
16:28 <@Nuclear> i C++ epidi anagnorizei oti ayto einai kati xrisimo
16:28 <@Nuclear> (to na min antigrafeis structs kai classes gia performance)
16:28 <@Nuclear> alla anangorizei kai oti ayto einai manoura giati prepei na kaneis dereferences  pantou
16:28 <@Nuclear> prosthetei ena kainourio feature
16:28 <@Nuclear> ayto to feature legetai "reference"
16:29 <@Nuclear> to reference einai ousiastika pointer, alla krymeno pointer
16:29 <@Nuclear> diladi to xrisimopoieis akrivos opos tha xrisimopoiouses to idio to antikeimeno, oxi pointer se antikeimeno
16:29 <@Nuclear> kai ayto kanei aytomata dereference
16:29 <@Nuclear> opote
16:30 <@Nuclear> ayti tin "pio grigori" add_complex, stin C++ mporeis na tin grapseis anti gia pointers, me references os eksis:
16:30 <@Nuclear> ComplexNum add_complex(ComplexNum &a, ComplexNum &b)
16:30 <@Nuclear> {
16:30 <@Nuclear>     return ComplexNum(a.re + b.re, a.im + b.im);
16:30 <@Nuclear> }
16:30 <@Nuclear> to & stis parametrous edo DEN einai to address operator pou exoume dei os tora
16:31 <@Nuclear> alla einai oti to a kai to b einai "references"
16:31 <@Nuclear> diladi pointers, pou omos xrisimopoiounte san kanonika antikeimena
16:31 <@Nuclear> otan to kaneis ayto, ap'ekso gia na tin kaleseis episis den xreiazetai na ta antimetopiseis san pointers
16:31 <@Nuclear> pernas parametrous akrivos opos tha pernouses an ginotan copy
16:31 <@Nuclear> ComplexNum c = add_complex(a, b);
16:32 <@Nuclear> kai epidi o compiler vlepei oti i add_complex pairnei references san arguments, ypologizei to address tou a kai tou b aytomata kai to pernaei
16:32 < gkops> aaaaaa malista 
16:32 < gkops> se swzei apo poly kopo diladi 
16:32 <@Nuclear> prosoxi omos sto eksis
16:32 <@Nuclear> afou ta references einai ousiastika pointer sto original "ekso" antikeimeno
16:32 <@Nuclear> an pas mesa sti synartisi kai kaneis a.re = 10;
16:33 <@Nuclear> atyo tha allaksei to original a pou eixes ap'ekso ekei pou tin kaleses
16:33 <@Nuclear> (giati einai to idio san na pernouses pointer, kai na ekanes a->re = 10;
16:33 <@Nuclear> )
16:33 <@Nuclear> opote erxomaste sto teleytaio pragma pou thelo na sou po simera
16:34 <@Nuclear> otan pernas reference se synartisi (i kai pointer), kai o *monos* logos pou xrisimopoieis reference (i pointer) einai gia performance, kai OXI epidi THELEIS na allaksei i synartiis kati sto ekso antikeimeno
16:34 <@Nuclear> PANTA, tha diloneis to argument me const mprosta
16:34 <@Nuclear> diladi
16:34 <@Nuclear> ComplexNum add_complex(const ComplexNum &a, const ComplexNum &b)
16:35 <@Nuclear> etsi otan vlepeis ayti ti synartiis se ena header file, ksereis oti de tha sou peiraksei tipota otan tin kaleseis
16:35 <@Nuclear> kai an katalathos kaneis modify kati mesa sti synartisi xoris na to thes, o compiler tha sou bgalei error
16:35 <@Nuclear> ayto loipon
16:35 <@Nuclear> to na pernas const references
16:35 <@Nuclear> gia logous performance
16:35 <@Nuclear> einai toso synithismeno, pou tha elega oti einai idiomatic stin C++
16:36 <@Nuclear> kai otan vlepeis parametro me reference (o pointer) xoris const, katalabaineis oti tha thelei na sto kanei modify
16:36 <@Nuclear> kai to idio isxyei kai sta operators pou sou elega prin
16:36 <@Nuclear> thelo na min ta diloseis: ComplexNum operator+(ComplexNum a, ComplexNum b);  opos elega mexri tora
16:37 <@Nuclear> alla:
16:37 <@Nuclear> ComplexNum operator+(const ComplexNum &a, const ComplexNum &b)
16:37 < gkops> a malista katalava 
16:37 <@Nuclear> olos o ypoloipos kodikas menei idios (mias kai ta references ginontai aytomata dereference kai address-of opou xreiazetai) alla kerdizeis to performance tou na min kaneis antigrafa ton objects
16:38 <@Nuclear> kai tora pao na tin kano :)
16:38 < gkops> ara prepei na mou ginei deyteri fysi 
16:38 <@Nuclear> ksanadiabase ta ayta kai prospathise na to kaneis
16:38 <@Nuclear> kai oti apories exeis, pes sto skype
16:38 < gkops> ok egine tha ta meletisw
16:38 <@Nuclear> se ayto to kanali tha ksanampoume otan theloume na poume poly text, pros to paron bgaino
16:38 < gkops> thanks gia to mathima ta leme meta :)
16:38 <@Nuclear> no problem
16:38 <@Nuclear> ta leme
--- Log closed Fri Feb 09 16:38:47 2018