Const指针与类

类的成员函数在调用的时候,会有一个隐式的this指针,默认情况下,这个指针的类型是 ClassName * const this,这意味着this指针不能改变,但this指针指向的对象是可以改变的。

但如果成员函数不会改变对象本身,那么this指针应该被设计为const ClassName * const this,即this指针是一个指向常量的常量指针,其指向的对象不可变更,本身也不可变更。

但因为this是隐式的指针,那么当我们想要声明this指针指向的对象是常量时,我们在哪里声明呢?

就在成员函数的参数后面,加一个const。这就叫常量成员函数。

注意,常量的对象无法调用自身的非常量成员函数,原因就在于,非常量成员函数的this指针是:ClassName * const this,无法指向一个const的对象。

Const指针与类》有51个想法

  1. Emilio

    Could I borrow your phone, please? write essay cheap The Reserve Bank of India is due to review monetary policyon Oct. 29, with a rising pace of inflation bolstering odds foranother central bank interest rate hike even as the economystumbles through its worst crisis since 1991.

  2. Emmett

    Have you got any experience? buy viagra 100mg “I think George Zimmerman is a man whose heart was in the right place, but just got displaced by the vandalism in the neighborhoods, and wanting to catch these people so badly, that he went above and beyond what he really should have done,” the woman said, speaking from behind a shadow to hide her identity.

  3. Benny

    Do you know the address? write essay fast
    Lending isn’t willy-nilly: borrowers are cherry-picked by credit checks, and rated according to risk. These websites do all the repayment chasing on your behalf – so there’s none of the legwork you’d have if you were lending cash to a fella down the pub.

  4. Jaime

    I work for myself cheap viagra online
    Critics point to the disclosure of diplomatic cables and say that by disclosing confidential contacts between US embassies and individuals living under sometimes repressive regimes, he placed individuals into positions of danger, perhaps forcing some into hiding. Critics say it also had a wider chilling effect on people's willingness to talk to US officials. They say confidential contacts are a necessary part of diplomacy.

  5. Noble

    very best job cheap cialis online Despite the crucial international aid to avoid default and a supplementary write-down of its debt load by some 100 billion euros last year, at the end of the first half of 2013 Greece still had a 321 billion euro debt, according to the latest official data, which is considered unsustainable by some analysts.

  6. Shelby

    I came here to study buy cialis 10mg
    The new tablet comes with a $30 price increase over last year’s model. At $229 for the base model, it is still a bargain — and 30 percent cheaper than Apple’s $329 iPad Mini. The display is sharper and the sound is richer than the old model. There’s now a rear camera for taking snapshots. The new Nexus 7 is the first device to ship with Android 4.3, which lets you create profiles to limit what your curious and nosy kids can do on your tablet when you’re not around.

  7. Freddy

    The line’s engaged write essay cheap As late as this week, Oregon also had trouble correctlydisplaying information about insurance plans on a test site. Theproblem could mislead customers about deductibles, prices andother details if it occurs on the live site Tuesday.

  8. Lioncool

    Until August buy cialis 10mg
    South of Safira, at least 20 Syrian troops and seven rebel fighters were killed in a dawn attack by rebels on an air defense base. There have been regular clashes in the region in recent weeks as Assad’s forces have sought to open up a supply route from the south to Aleppo, bypassing the main north-south highway which is partly under rebel control.

  9. Sydney

    I stay at home and look after the children cheap viagra online
    Kenya has called for the cases to be dropped or moved closer to home. It has also rallied African support against the ICC, which has until now charged only Africans. The arrest warrant will test Kenya’s stated commitment to cooperate with the court.

  10. Derrick

    How long are you planning to stay here? buy viagra 100mg “We will not protect anyone who commits a crime involving public funds, which are sacred because they are the people's money. There are no untouchables here,” Francisco Ameliach, the governor of Carabobo state and another member of the ruling party, told state media.

  11. Franklin

    It’s a bad line write essay fast
    Illnesses associated with eating the Costco chicken are part of a larger outbreak tied to three Foster Farms production sites in Fresno and Livingston, Calif. USDA officials issued a public health alert for raw chicken made by the firms this month and threatened to close the sites by withholding inspections. But Foster Farms agreed to fix the problems that led to the contamination and federal officials agreed to allow the sites to remain open. 

  12. Harland

    A pension scheme cheap viagra online
    The 44 children rotting in Israel's jails are not on the list of prisoners the Israeli cabinet signed off on releasing in exchange for Abbas and his cronies agreeing to come back to the infamous negotiating table. The jailbirds set to be freed are not your average Palestinian prisoners and have all been doing time since before the signing of the Oslo Accords, by Arafat and Rabin, in 1993. These men are not being indefinitely detained without charges and were convicted by Israel of far worse things than tossing rocks at IDF tanks. This little detail helps to bolster Israel's PR machine by reenforcing the myth that all Palestinians are terrorists and Israel is putting her very existence at risk by agreeing to sit with these monsters again. Netanyahu also gets to drone on about how poor Israel got nothing in return for agreeing to reengage. He conveniently ignores the fact that billions of U.S. tax dollars continuously flow Israel's way and  America has, yet again, turned a blind eye and a deaf ear to the sights and sounds of Israeli bulldozers expanding the illegal settlements as Kerry, Livni and Erekat speak.

  13. Zachery

    very best job buy cialis 10mg
    Danoff, 53, has run New Insights for a decade. He is bestknown for his 23-year run at Contrafund. Over the past 20 years,Contrafund is No. 1 out of 53 large-cap growth funds withannualized returns of 10.33 percent, as of Aug. 31, according toLipper Inc data.

  14. Cliff

    I’m on business cheap viagra online
    Almunia said it would be much easier for a user to see competing services in Google search results irrespective of which device was being used. Rival firms had worried that even if concerns around computers were addressed, search results displayed on smaller devices such as mobiles could still prevent them from appearing prominently.

  15. Lawerence

    History cheap cialis online After three years in the U.S. Army, he served with the Chicago Police Department for 18 years, both as a uniformed officer (he was there for the 1968 Chicago riots) and a burglary detective, before he found his way into acting as he neared his forties.

  16. Tommy

    How much is a First Class stamp? cheap viagra online
    The infighting has undermined the rebel military campaign against President Bashar al-Assad. Their uprising began as peaceful protests against four decades of Assad family rule but degenerated into a war that has killed more than 100,000 people.

  17. Fausto

    No, I’m not particularly sporty write essay cheap When firefighters got to the scene, “we opened the front door and could see the fire in the back,” fire Chief John Bley said. It was unclear what caused the explosion on the first floor, he said, and there was a minor collapse inside the building but nothing structural.

  18. Gracie

    A jiffy bag write essay cheap Smithfield said on Wednesday that the U.S. government hasdecided to take an additional 45 days to review the planneddeal. Smithfield and Shuanghui submitted their proposal in Juneto the Committee on Foreign Investment in the United States, orCFIUS, an executive branch panel that examines foreigninvestment for potential threats to national security.

  19. Domenic

    Can I call you back? write essay fast
    According to ComingSoon.net, Larry Charles said that the pilot, “was really good, but … I think it was too hard-core for HBO. Also, HBO’s management shifted. HBO doesn’t have a good track record when it comes to black shows, and I felt like that may have had something to do with it also.”

  20. Gavin

    How many would you like? cheap cialis online Environment Canada said some parts of the city had been drenched with more than 100 millimetres of rain in Monday evening’s storm, easily beating the previous one-day rainfall record of 36 millimetres in 2008.

  21. Issac

    A financial advisor buy cialis 10mg
    A spokesman for the Food Standards Agency says in an emailed statement: “Independent experts from the Committee on Toxicity recently reviewed aluminium in the infant diet, including the levels of aluminium present in infant formula and taking into account the water used in reconstitution.

  22. Ervin

    A financial advisor write essay fast
    They also asked for the names of the key executives at Smithfield Foods involved in the manufacturing and marketing of heparin products, including pig intestines and crude heparin, and details of key managers at any Smithfield facility involved in manufacturing crude heparin.

  23. Carlo

    We went to university together buy cialis 10mg
    If the Court of Cassation rejects Berlusconi’s appeal he could serve only one year of his sentence due to a 2006 amnesty law, and at the age of 76 he would likely be granted house arrest, but he challenged judges to put him behind bars.

  24. Vicente

    I love the theatre cheap viagra online
    Deutsche Boerse rival The London Stock Exchange last weakbeat expectations for its fiscal first quarter revenues, helpedby acquisitions as well as improving sentiment which has helpedmarket volumes.

  25. Oliver

    Cool site goodluck 🙂 cheap cialis online “Just getting selected for the All-Star Game was a real feather in your hat because in those days, the players voted, so it wasn’t a popularity contest,” Koosman adds. “It was all that I thought it would be and then to enter the game with one swing of the bat on the line, winning or lose, you feel like you’re walking on air.”

  26. Dominick

    Best Site good looking buy viagra 100mg This is what you’d expect at media day from a team with high-priced veterans, a collection of winners who said all the right things Monday —they’ll lead by example, they’ll sacrifice their shots and stats, they’re removing all egos from a locker room filled with All-Stars.

  27. Rolland

    Do you play any instruments? write essay cheap “If we decide a new CEO has the same commitment that SteveBallmer had, then we will go forward with the transition,” YahooSenior Vice President of Search Products Laurie Mann is quotedas testifying in the court filings.

  28. Bertram

    perfect design thanks cheap cialis online The Great Barrier Reef Marine Park Authority, the government manager of the 345,400 square kilometer (133,360 square miles) protected marine zone, said in a statement that identifying options for the “rapid recovery” of the bombs so that they could pose no risk to the marine park was “a high priority.”

  29. Wilfred

    What do you want to do when you’ve finished? buy viagra 100mg One evening, although we felt it was slightly cheesy, we overcame our cynicism and hired a gondola, which was well worth the £60 (not an amount I part with lightly). Moreover, to our delight, we happened to be following in the wake of a couple who had a tenor worthy of La Scala serenading them on board, so we listened for free.

  30. Osvaldo

    I’m self-employed buy viagra 100mg The agency, which offers private mortgage lenders guaranteesagainst homeowner default, has nearly exhausted its reserves forthe mortgages it backs. Housing officials have yet to determinehow much money the FHA may need to draw, the sources said.

  31. Mitch

    How do you do? write essay fast
    Some of the similarities were literal. Both were movies set in outer space, and if one was hyper-realistic and the other fantastical, they both showed us the possibility of something rich that lies beyond our earthly grasp. Both indeed demanded (and received) an unusually wide viewership in that third dimension, after years in which the format seemed dormant. Both are about talented scientists in over their head trying to get home. Both also opened big and seemed to gain momentum as they went. (“Gravity” is on a high trajectory, though “Avatar’s” eye-popping global total of $2.8 billion may never be caught by any movie.)

  32. Johnie

    I’ve come to collect a parcel cheap cialis online So we spoke to Dr. Norton, a professor at Harvard Business School, to find out what little tricks we can do — like splurging on a nice dinner out with friends, instead of shelling out for a high-def TV — to score the most happiness bang for our buck.

  33. Toney

    I like it a lot cheap viagra online
    “She can claim all she wants that something was said that was false. My client didn’t write any of it. My client simply runs a website where people talk,” Gingras told WCPO-TV. “If Sarah changes the law and has website owners held responsible for other people’s words, there’s no Facebook.

  34. Manual

    What do you study? cheap cialis online Though only a small percentage of S&P 500 stocks havereported earnings thus far, the season has been mixed, withrevenue growth especially a concern. Still, profits have largelyrisen and many bellwether companies have topped expectations.

  35. Andreas

    I’ve just started at kamagra ksa “If I have to respond to some of the amendments that I have seen in an open session, it’s not a fair fight,” Young said, arguing that he would be hampered by secrecy rules in trying to respond to critics. “The only argument that my wife and I have ever have is she wants to know what I know and I tell her, ‘I can’t tell you what I know.’”

  36. Maximo

    Have you got any experience? write essay fast
    The 54-43 roll call — six short of the 60 votes needed to invoke cloture — comes on the heels of Wednesday’s decision by the House GOP leadership to pull its own $44.1 billion version of the same bill.

  37. Lincoln

    I was made redundant two months ago buy viagra 100mg Sopko and others raised alarm at the fact the project continued despite the diminishing need for it. In his letter, Sopko said it appeared to be one of the “best constructed” buildings he’s seen in the country. 

  38. Oscar

    I’m a member of a gym buy viagra 100mg The weapons maker said about 3,000 employees would befurloughed on Monday due to the U.S. shutdown. The number ofemployees was expected to increase every week if the shutdowncontinued, the company said.

  39. Russell

    A staff restaurant write essay fast
    Massino has served 101/2 years since he was arrested at Queens, faux mansionhome. He subsequently handed over his fortune: $7.6 million in cash, 257 gold bars stashed in his attic and the CasaBlancaCQ restaurant he controlled.

  40. Truman

    Will I have to work shifts? levitra paypal They are also vital to Delaware’s economy. Most of the largest U.S. businesses are incorporated in Delaware, even if they have no operations in the state, because of its long-established case law and the consistency of its courts. Around 40 percent of Delaware’s general revenue is tied in some way to chartering businesses.

  41. Mishel

    I’d like a phonecard, please buy viagra 100mg “It’s one of those things where they do have some local support in that regard. But it’s not necessarily support for al Qaeda or support for the Taliban, in as much as they have been up there long enough that they have perhaps been accepted by some of the people.”

  42. Diana

    A packet of envelopes write essay fast
    Still, agreement in Washington remains elusive, with the partial government shutdown that began on Tuesday appearing likely to drag on for another week or possibly longer, with the next crisis in sight on October 17.

  43. Lavern

    How much is a Second Class stamp? cheap viagra online
    In 2011 we have agreed on exchanging best practices between police forces. A pilot project successfully took place in the 2nd half of 2012 when 10 Romanian police officers worked alongside their British colleagues. Due to the excellent results, the MET submitted an application for EU funding, approved as Operation Nexus, which includes the participation of other EU member states as well. The current secondment of Romanian police officers within the Metropolitan Police is, therefore, a natural follow up to this model bilateral cooperation we have developed over the last couple of years.

  44. Felix

    I’m on a course at the moment write essay fast
    Brahimi said it was possible to find a political solution in efforts to bring together the warring parties for a peace conference in Geneva. “It is extremely difficult to bring (together) people who have been killing one another for two years just by waving a magic wand to a conference like this. It will take time but I hope it will happen.”

  45. Peter

    I’m on business cheap viagra online
    (5) while airpower could be used to reduce the Assad regime’s ability or desire to launch large-scale chemical attacks, eliminating its chemical weapon arsenal would require a large ground operation. Any of these actions would involve substantial risks of escalation by third parties, or could lead to greater U.S. military involvement in Syria.

  46. Cleveland

    I’m retired cheap viagra online
    “It was amazing for Harry to make that call 15 minutes after the game just to say how well he’s done and how much he believed in him and the future that he has as well and I can’t commend Harry enough for giving him the opportunity to be on this platform,” Troy Townsend said.

评论已关闭。