Video: Dab tsi yog null array?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
null array --thaum qhov loj ntawm array tsis tshaj tawm tshaj qhov array yog lub npe hu ua null array . EMPTY ARRAY --- if ib array muaj qhov loj me tab sis tsis muaj nuj nqis tshaj qhov nws paub tias yog khoob array.
Ib yam li ntawd, ib qho array puas tuaj yeem ua tsis tau Java?
Ib int array tsis muaj ntsiab yog tsis tas null . Nws yuav tsuas yog ua null yog nws tseem tsis tau faib. Saib daim ntawv qhia no kom paub ntau ntxiv txog Java arrays . Koj ua tau kuj xyuas seb puas muaj cov ntsiab lus hauv lub array los ntawm kev nrhiav nws qhov ntev, ces muab tso rau hauv yog-lwm nqe lus los xyuas seb nws puas yog null.
Ib sab saum toj no, koj yuav ua li cas xyuas seb qhov array puas yog null lossis tsis?
- Siv suav Function: Qhov haujlwm no suav tag nrho cov ntsiab lus hauv ib qho array. Yog tias tus naj npawb ntawm cov ntsiab lus hauv array yog xoom, ces nws yuav tso tawm cov array khoob.
- Siv sizeof() muaj nuj nqi: Txoj kev no xyuas qhov loj ntawm array. Yog hais tias qhov loj ntawm array yog xoom ces array yog npliag txwv tsis pub array tsis yog khoob.
Tom qab ntawd, lo lus nug yog, koj tuaj yeem teeb tsa ib qho array rau null?
Yog koj muaj ib array ntawm integers thiab koj sim ua ib lub caij null koj ua tau 't ua arr = null ; vim integer tsis tuaj yeem hloov mus rau null . Tsis yog kiag li. Nyob rau hauv thawj rooj plaub koj 're kev teeb tsa tag nrho cov ntaub ntawv nyob rau hauv koj array rau null . Hauv qhov thib ob koj 're kev teeb tsa qhov siv heev rau lub array nws tus kheej rau null.
Dab tsi yog qhov sib txawv null?
Null . Thaum a sib txawv tsis muaj nuj nqis, nws suav tias yog null . Muaj ib null tus nqi txawv dua li muaj tus nqi ntawm 0, vim 0 yog tus nqi tiag tiag. Programmers feem ntau siv boolean xeem los txiav txim seb a sib txawv tau muab tus nqi los tsis tau.
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