什么是实例化?

這是一個推薦產品對話框
熱門建議
起價
查看全部 >
語言
French
English
ไทย
German
繁體中文
國家/地區
All
登入/建立帳戶
language Selector,${0} is Selected
註冊並於Lenovo Pro 商務採購商店購物
於Lenovo教育商店註冊

專業等級福利

• 在 Think 每日價格上節省高達額外 3%
• 消費滿HK$78,000,晉升至 Plus 等級,享有更多福利

Plus 等級福利

• 在 Think 每日價格上節省高達額外 5%
• 消費滿HK$120,000,免費升級至擁有更多福利的菁英等級
等菁英級福利
• 在Think日常價格上節省高達額外8%
經銷商福利
• 可獲得Lenovo全系列產品的使用權
• 配置和購買價格優於Lenovo.com
查看所有詳情 >
再多達到
PRO Plus
PRO 菁英
恭喜,您已達到菁英地位!
Pro for Business
Delete icon Remove icon Add icon Reload icon
即將上市
已停產
暫時無法使用
Cooming Soon!
. Additional units will be charged at the non-eCoupon price. Purchase additional now
We're sorry, the maximum quantity you are able to buy at this amazing eCoupon price is
登入或建立帳戶以儲存您的購物車!
Sign in or Create an Account to Join Rewards
檢視購物車
Wow, your cart is empty!
移除
items in cart
Fill it in with great deals
Some items in your cart are no longer available. Please visit cart for more details.
has been deleted
Please review your cart as items have changed.
/
Contains Add-ons
繼續進行結帳
是的
Popular Searches
今天您想找什麼?
Quick Links
Recent Searches
Hamburger Menu
跳至主要內容
{"arrowColor":"#000000","backgroundColor":"#e6f4fa","divideColor":"","sideMsg":"","data":[{"pcInfo":"","mAndTabInfo":"","bannerInfo":{"t_id":"Page8846652c-9bc3-42f6-a990-1fa07407938e","language":{"zh_hk":"%3Cp%20style%3D%22text-wrap%3A%20wrap%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%E5%8A%A0%E5%85%A5%20Lenovo%20Pro%20%E5%8D%B3%E5%8F%AF%E4%BA%AB%E9%AB%98%E9%81%948%E6%8A%98%E8%BF%8E%E6%96%B0%E5%84%AA%E6%83%A0%3C%2Fspan%3E%3C%2Fp%3E%3Cp%20style%3D%22text-wrap%3A%20wrap%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%E8%87%B4%E9%9B%BB%26nbsp%3B%3C%2Fspan%3E%3Cspan%20style%3D%22color%3A%20rgb(255%2C%20255%2C%20255)%3B%22%3E%3Ca%20href%3D%22tel%3A25930388%22%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%22%3E%3Cstrong%3E2593%200388%3C%2Fstrong%3E%3C%2Fa%3E%26nbsp%3B%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%E8%A7%A3%E9%8E%96%E5%84%AA%E6%83%A0%26nbsp%3B%20%26nbsp%3B%20%26nbsp%3B%26nbsp%3B%3C%2Fspan%3E%3C%2Fspan%3E%3Ca%20href%3D%22%2Fbusiness%2Fbenefits%2F%3FipromoID%3Dhellobar_01_lpro_learn%22%20target%3D%22_blank%22%20textvalue%3D%22%E5%85%8D%E8%B2%BB%E5%8A%A0%E5%85%A5%22%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%20text-decoration%3A%20underline%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%E5%85%8D%E8%B2%BB%E5%8A%A0%E5%85%A5%3C%2Fstrong%3E%3Cstrong%3E%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fp%3E","en":"","en_hk":"%3Cp%20style%3D%22text-wrap%3A%20wrap%3B%22%3E%3Cspan%20style%3D%22font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3EJoin%20Lenovo%20Pro%20for%20up%20to%2010%25%20Welcome%20Discount.%3C%2Fspan%3E%3C%2Fp%3E%3Cp%20style%3D%22text-wrap%3A%20wrap%3B%22%3E%3Ca%20href%3D%22tel%3A25930388%22%20style%3D%22color%3A%20rgb(255%2C%20255%2C%20255)%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%22%3E%3Cstrong%3ECall%202593%200388%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3Cspan%20style%3D%22font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3E%3Cstrong%3E%3Cspan%20style%3D%22font-family%3A%20Montserrat%3B%20color%3A%20rgb(255%2C%20255%2C%20255)%3B%22%3E%26nbsp%3B%20%26nbsp%3B%20%26nbsp%3B%3C%2Fspan%3E%3C%2Fstrong%3E%26nbsp%3B%3C%2Fspan%3E%3Ca%20href%3D%22%2Fbusiness%2Fbenefits%2F%3FipromoID%3Dhellobar_01_lpro_learn%22%20target%3D%22_self%22%20textvalue%3D%22Join%20For%20Free%22%3E%3C%2Fa%3E%3Ca%20href%3D%22%2Fbusiness%2Fbenefits%2F%3FipromoID%3Dhellobar_01_lpro_learn%22%20target%3D%22_blank%22%20textvalue%3D%22JOIN%20FOR%20FREE%22%20style%3D%22text-decoration%3A%20underline%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%3Cstrong%3EJoin%20For%20Free%3C%2Fstrong%3E%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fp%3E","zh":""},"id":"Page8846652c-9bc3-42f6-a990-1fa07407938e"},"gInfo":""},{"pcInfo":"","mAndTabInfo":"","bannerInfo":{"t_id":"Pagef18b576c-473e-4c4f-8b62-ea86b00c66c0","language":{"zh_hk":"%3Cp%20style%3D%22text-wrap%3A%20wrap%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%E5%8A%A0%E5%85%A5%20Lenovo%20Edu%EF%BC%8C%E5%8D%B3%E4%BA%AB%E9%AB%98%E9%81%94%24800%E8%BF%8E%E6%96%B0%E6%8A%98%E6%89%A3%3C%2Fspan%3E%3C%2Fp%3E%3Cp%20style%3D%22text-wrap%3A%20wrap%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%E8%87%B4%E9%9B%BB%3C%2Fspan%3E%3Cspan%20style%3D%22color%3A%20rgb(255%2C%20255%2C%20255)%3B%22%3E%26nbsp%3B%3Ca%20href%3D%22tel%3A25930388%22%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%20text-decoration%3A%20underline%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%22%3E%3Cstrong%3E%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3Cstrong%3E%3Ca%20href%3D%22tel%3A25930388%22%20style%3D%22text-wrap%3A%20wrap%3B%20color%3A%20rgb(255%2C%20192%2C%200)%3B%22%3E%3Cstrong%3E2593%200388%3C%2Fstrong%3E%3C%2Fa%3E%3C%2Fstrong%3E%3C%2Fspan%3E%26nbsp%3B%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%E8%A7%A3%E9%8E%96%E5%84%AA%E6%83%A0%26nbsp%3B%3C%2Fspan%3E%26nbsp%3B%20%26nbsp%3B%3Ca%20href%3D%22%2Flenovo-edu%2Fstudent%2Fbenefits%2F%3FipromoID%3Dhellobar_02_edu%22%20target%3D%22_blank%22%20textvalue%3D%22%E5%85%8D%E8%B2%BB%E5%8A%A0%E5%85%A5%22%20style%3D%22text-decoration%3A%20underline%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%E5%85%8D%E8%B2%BB%E5%8A%A0%E5%85%A5%3C%2Fstrong%3E%3Cstrong%3E%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%26nbsp%3B%3C%2Fspan%3E%3C%2Fp%3E","en":"","en_hk":"%3Cp%20style%3D%22text-wrap%3A%20wrap%3B%22%3EJoin%20Lenovo%20Edu%20and%20enjoy%20up%20to%20%24800%20Welcome%20Discount%3C%2Fp%3E%3Cp%20style%3D%22text-wrap%3A%20wrap%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%20font-family%3A%20Montserrat%3B%22%3E%26nbsp%3B%3Ca%20href%3D%22tel%3A25930388%22%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%20text-decoration%3A%20underline%3B%22%3E%3Cstrong%3E%3C%2Fstrong%3E%3C%2Fa%3E%3Cstrong%3E%3Ca%20href%3D%22tel%3A25930388%22%20style%3D%22text-wrap%3A%20wrap%3B%20color%3A%20rgb(255%2C%20255%2C%20255)%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%22%3E%3Cstrong%3ECall%202593%200388%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fstrong%3E%26nbsp%3B%20%26nbsp%3B%3Ca%20href%3D%22%2Flenovo-edu%2Fstudent%2Fbenefits%2F%3FipromoID%3Dhellobar_02_edu%22%20target%3D%22_blank%22%20textvalue%3D%22Join%20For%20Free%22%20style%3D%22text-decoration%3A%20underline%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3E%3Cstrong%3EJoin%20For%20Free%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fspan%3E%3C%2Fp%3E","zh":""},"id":"Pagef18b576c-473e-4c4f-8b62-ea86b00c66c0"},"gInfo":""},{"pcInfo":"","mAndTabInfo":"","bannerInfo":{"t_id":"Page759f67ac-d7b2-45fd-b35c-1589871aa30e","language":{"zh_hk":"%3Cp%3E%3Cspan%20style%3D%22text-wrap%3A%20wrap%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%E6%9C%89%E7%96%91%E5%95%8F%E5%97%8E%EF%BC%9F%20%E5%A6%82%E9%9C%80%E6%88%91%E5%80%91%E7%9A%84%E5%B0%88%E5%AE%B6%E5%BB%BA%E8%AD%B0%EF%BC%8C%E8%AB%8B%E8%87%B4%E9%9B%BB%3C%2Fspan%3E%3Cspan%20style%3D%22text-wrap%3A%20wrap%3B%20color%3A%20rgb(255%2C%20255%2C%20255)%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3E%26nbsp%3B%3Ca%20href%3D%22tel%3A25930388%22%20style%3D%22color%3A%20rgb(255%2C%20255%2C%20255)%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%22%3E%3Cstrong%3E2593%200388%3C%2Fstrong%3E%3C%2Fspan%3E%3Cspan%20style%3D%22text-wrap%3A%20wrap%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%E6%88%96%E9%BB%9E%E6%93%8A%E3%80%8C%E8%81%8A%E5%A4%A9%E3%80%8D%EF%BC%81%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fspan%3E%3Cspan%20style%3D%22text-wrap%3A%20wrap%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%26nbsp%3B%26nbsp%3B%3C%2Fspan%3E%3Ca%20target%3D%22_self%22%20class%3D%22live_chat_daily%22%20style%3D%22text-wrap%3A%20wrap%3B%20text-decoration%3A%20underline%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%E8%81%AF%E7%B5%A1%E6%88%91%E5%80%91%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fp%3E","en":"","en_hk":"%3Cp%3E%3Cspan%20style%3D%22text-wrap%3A%20wrap%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3ENeed%20Help%3F%3C%2Fspan%3E%3Cspan%20style%3D%22text-wrap%3A%20wrap%3B%20color%3A%20rgb(255%2C%20255%2C%20255)%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3E%26nbsp%3B%26nbsp%3B%3Ca%20href%3D%22tel%3A25930388%22%20style%3D%22color%3A%20rgb(255%2C%20192%2C%200)%3B%22%3E%3Cstrong%3ECall%202593%200388%3C%2Fstrong%3E%3C%2Fa%3E%26nbsp%3B%26nbsp%3B%3C%2Fspan%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cspan%20style%3D%22text-wrap%3A%20wrap%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3Eor%20Chat%20with%20us%20now!%3C%2Fspan%3E%3Cspan%20style%3D%22text-wrap%3A%20wrap%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%22%3E%26nbsp%3B%26nbsp%3B%3C%2Fspan%3E%3C%2Fspan%3E%3Ca%20target%3D%22_self%22%20class%3D%22live_chat_daily%22%20style%3D%22text-wrap%3A%20wrap%3B%20text-decoration%3A%20underline%3B%20font-family%3A%20arial%2C%20helvetica%2C%20sans-serif%3B%20color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3EContact%20Us%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fp%3E","zh":""},"id":"Page759f67ac-d7b2-45fd-b35c-1589871aa30e"},"gInfo":""},{"pcInfo":"","mAndTabInfo":"","bannerInfo":{"t_id":"Paged1b2a6fe-709a-431e-922f-39376e777ab2","language":{"zh_hk":"%3Cp%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%3C%2Fstrong%3E%3Cstrong%3E%E3%80%90%E5%B9%B4%E4%B8%AD%E9%96%8B%E5%80%89%E5%8B%81%E6%B8%9B%E3%80%91%3C%2Fstrong%3E%20%E9%9B%BB%E8%85%A6%E4%BD%8E%E8%87%B36%E6%8A%98!%20%E4%BD%BF%E7%94%A8%E5%84%AA%E6%83%A0%E7%A2%BC%20%26%2339%3BMIDYEARHK%26%2339%3B%20%E9%A1%8D%E5%A4%96%E6%9C%80%E5%A4%9A%E6%B8%9B%241%2C000%26nbsp%3B%20%26nbsp%3B%20%26nbsp%3B%26nbsp%3B%3C%2Fspan%3E%3Ca%20href%3D%22%2Fd%2Fdeals%2Fspecial-offer%2F%3FipromoID%3Dhellobar_sitewide_promo%22%20target%3D%22_self%22%20textvalue%3D%22%E6%9C%83%E5%93%A1%E7%8E%87%E5%85%88%E6%90%B6%E8%B3%BC%22%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%20text-decoration%3A%20underline%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%E6%9C%83%E5%93%A1%E7%8E%87%E5%85%88%E6%90%B6%E8%B3%BC%3C%2Fstrong%3E%3Cstrong%3E%3C%2Fstrong%3E%3Cstrong%3E%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fp%3E","en":"","en_hk":"%3Cp%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3C%2Fspan%3E%3C%2Fp%3E%3Cp%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%3C%2Fstrong%3E%3Cstrong%3E%E3%80%90Mid-Year%20Mega%20Sale%E3%80%91%3C%2Fstrong%3EPCs%20up%20to%2040%25%20off.%20Use%20coupon%20code%20%26%2339%3BMIDYEARHK%26%2339%3B%20to%20save%20up%20to%20extra%20%241%2C000%26nbsp%3B%20%26nbsp%3B%20%26nbsp%3B%26nbsp%3B%3C%2Fspan%3E%3Ca%20href%3D%22%2Fd%2Fdeals%2Fspecial-offer%2F%3FipromoID%3Dhellobar_sitewide_promo%22%20target%3D%22_self%22%20textvalue%3D%22Exclusively%20for%20Members%22%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%20text-decoration%3A%20underline%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3EExclusively%20for%20Members%3C%2Fstrong%3E%3Cstrong%3E%3C%2Fstrong%3E%3Cstrong%3E%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fp%3E","zh":""},"id":"Paged1b2a6fe-709a-431e-922f-39376e777ab2"},"gInfo":""},{"pcInfo":"","mAndTabInfo":"","bannerInfo":{"t_id":"Page9918dcb1-0cb7-48ee-9791-6da2dca00a2f","language":{"zh_hk":"%3Cp%3EYoga%20Slim%207%20AI%20PC%20%7C%20%E9%80%8F%E9%81%8E%E6%90%AD%E8%BC%89Snapdragon%C2%AE%20X%20Elite%E8%99%95%E7%90%86%E5%99%A8%E7%9A%84%E5%85%A8%E6%96%B0Lenovo%20Yoga%20Slim%207x%E3%80%82%26nbsp%3B%20%26nbsp%3B%3Ca%20href%3D%22%2Fp%2Flaptops%2Fyoga%2Fai-pc-series%2Fyoga-slim-7x-gen-9-(14-inch-qualcomm)%2Flen101y0049%3FipromoID%3Dhellobar_05_AI_PC%22%20target%3D%22_self%22%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3E%E7%AB%8B%E5%8D%B3%E9%A0%90%E8%A8%82%3C%2Fstrong%3E%3C%2Fa%3E%3C%2Fp%3E","en":"","en_hk":"%3Cp%3EYoga%20Slim%207%20AI%20PC%20%7C%20Level%20up%20your%20creativity%20with%20next-gen%20AI%20experiences%20on%20the%20new%20Lenovo%20Yoga%20Slim%207x.%26nbsp%3B%20%26nbsp%3B%3Ca%20href%3D%22%2Fp%2Flaptops%2Fyoga%2Fai-pc-series%2Fyoga-slim-7x-gen-9-(14-inch-snapdragon)%2Flen101y0049%3FipromoID%3Dhellobar_05_AI_PC%22%20target%3D%22_self%22%20textvalue%3D%22Pre-order%20Now%22%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%20text-decoration%3A%20underline%3B%22%3E%3Cspan%20style%3D%22color%3A%20rgb(0%2C%200%2C%200)%3B%22%3E%3Cstrong%3EPre-order%20Now%3C%2Fstrong%3E%3Cstrong%3E%3C%2Fstrong%3E%3C%2Fspan%3E%3C%2Fa%3E%3C%2Fp%3E","zh":""},"id":"Page9918dcb1-0cb7-48ee-9791-6da2dca00a2f"},"gInfo":""}],"autoRun":true,"displayTerminal":"pc,tablet,mobile","isShowDivide":true}

什么是实例化?

实例化是面向对象编程的一个核心概念。它是创建类实例的过程,本质上意味着从蓝图(类)中创建对象。当你实例化一个类时,你就把它赋予了生命,以便在你的程序中使用。

是否每个对象都需要实例化?

是的,在面向对象编程中,每个对象都必须先实例化才能使用。这是因为对象是类的实例,它们必须先从类蓝图中创建或 "复活",然后才能做任何事情。

在实例化过程中会发生什么?

在实例化过程中,会为新对象分配内存,并将其属性设置为初始值。然后调用类的构造方法(如果有的话)。该方法通常会设置对象的状态。

我能在不知道一个类的所有属性的情况下将其实例化吗?

可以。当你实例化一个类时,并不一定需要知道它的所有属性。不过,重要的是要知道有哪些方法和属性可供使用,这样才能正确使用对象。

在不同的编程语言中,实例化会有所不同吗?

是的,不同编程语言的实例化语法和具体步骤可能有所不同。但基本概念是相同的:创建一个类的实例,供程序使用。

何时应实例化一个类?

当你需要一个类的对象来执行程序中的某些操作时,你应该实例化这个类。具体时间取决于您的具体程序及其要求。

实例化与继承有关系吗?

是的,确实如此。继承是面向对象编程的一个重要特征,一个类可以继承另一个类的属性和方法。当你实例化一个子类时,它也可以初始化从其超类继承的属性。

我能拥有同一个类的多个实例吗?

当然,你可以根据需要创建任意多个类的实例。每个实例都是一个独立的对象,拥有自己的属性集。即使是同一个类的实例,它们的属性值也可以不同。

实例化是否总是需要使用 "new "关键字?

在许多面向对象编程语言(如 Java 或 C#)中,您通常会使用 "new "关键字来实例化一个类。但并不总是这样。例如,在 Python 中,您可以像调用一个函数一样调用它来实例化一个类,而不需要使用 "new "关键字。

什么是默认构造函数?我能在实例化中使用它们吗?

默认构造函数是一种不带参数的构造函数。在许多编程语言中,如果您没有在类中定义任何构造函数,系统会自动为您提供一个默认构造函数。您可以使用它来实例化类,而无需为其属性提供任何初始值。

实例化在内存分配中的作用是什么?

实例化一个类时,会为新对象分配内存。这些内存将保存对象的属性和方法。分配的具体内存量取决于类的大小和复杂程度。

静态方法能否访问实例变量或方法?

静态方法不能直接访问实例变量或方法。这是因为静态方法属于类,而不是类的任何实例。因此,静态方法无法访问该类实例特有的任何内容。

在面向对象编程中,实例化的目的是什么?

面向对象编程中的实例化有一个重要目的:创建类的实例。该实例或对象是类的实现,拥有自己的状态(数据)和行为(方法)。通过实例化类,可以使用类定义的蓝图创建具有特定状态和行为的对象。

我能在 Java 中实例化抽象类吗?

不能,您不能在 Java 中实例化抽象类。抽象类是使用关键字 abstract 声明的类。它可以包含抽象方法(没有主体的方法)和具体方法(有主体的普通方法)。抽象类的目的是作为子类的基类,提供一个多个子类可以共享的公共结构。要使用抽象类,必须先将其子类化,然后实例化子类。

什么是单例类,如何将其实例化?

Java 中的单例类是指只允许创建一个实例的类。要创建单例类,需要将构造函数设置为私有,以防止其他类将其实例化。然后提供一个公共静态方法,返回该类的单个实例。

可以在 Java 中实例化私有类吗?

在 Java 中,声明为私有的类不能在其外层类之外实例化。私有类通常用作其外层类的辅助工具,对同一软件包中的其他类是隐藏的。

什么是懒实例化,为什么要使用它?

懒实例化是一种编程技术,它将对象或值的创建或计算延迟到第一次需要时才进行。这种方法可以减少程序的内存占用,并通过在必要时才创建或计算值来提高性能。

可以在 Java 中实例化内部类吗?

是的,我们可以在 Java 中实例化一个内层类,但过程与顶级类略有不同,因为内层类与外层类相关联。要实例化一个内层类,首先需要一个外层类的实例。

在 Java 中,"无法实例化类型列表 "是什么意思?

错误信息 "无法实例化 List 类型 "通常意味着您正试图直接实例化一个接口或抽象类。在 Java 中,List 是一个接口,这意味着它不能被直接实例化。

new "关键字在实例化中有什么作用?

在许多编程语言(如 Java、C++ 和 C#)中,new 关键字用于实例化。使用 new 时,会发生以下情况:

在堆上为对象分配内存。

>

类的构造函数被调用来初始化对象。

返回对象的引用,该引用可以存储在变量中。

因此,new 关键字对于在这些语言中创建新对象至关重要。

open in new tab
© 2024 Lenovo. 保留所有權利。
© {year} Lenovo. All rights reserved.
比較  ()
x