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C 语言的输入输出函数 scanf() 和 printf()

scanf&printfC语言入门的第一堂课讲的就是输出 Hello,world! 字符串，使用 printf() 输出到黑框框（命令行）里。后面讲IO的时候又提到了 scanf() 从黑框框中获取输入的内容。基本的用法如下：intn;scanf("%...

开发笔记·2024-01-20

available: expected at least 1 bean which qualifies as autowire candidate

available:expectedatleast1beanwhichqualifiesasautowirecandidate这个错误我也是找了半天,最后排查的时候发现是自己的实现类写错了,所以注入不进去.出现这个错误一般有四个方向排查查看接口实现类是否加入注解，如service、repository等查看spring...

开发笔记·2023-10-20

前端如何用 canvas 来做电影院选票功能

电影院选票功能可以通过Canvas来实现，具体实现步骤如下：绘制座位图案：使用Canvas绘制座位图案，可以用矩形或圆形来表示每个座位，还可以添加不同颜色来表示该座位的状态（已售、已选、可选等）。添加鼠标事件：添加鼠标事件，如鼠标移动、鼠标单击等，来实现用户交互操作。例如，当用户点击座位时，将该座位的状态改为已选状态，...

开发笔记·2023-08-12

ORA-64143: Can only share an existing XMLIndex table with an XMLTYPE column.

文档解释ORA-64143:CanonlyshareanexistingXMLIndextablewithanXMLTYPEcolumn.Cause:AnattemptwasmadetoshareatablewithoutanXMLTYPEcolumn.Action:DropthegroupcontainingtheX...

IT技术学习·2023-07-28

ORA-44739: Cannot drop the last group.

文档解释ORA-44739:Cannotdropthelastgroup.Cause:Anattemptwasmadetodropthelastgroupintheindex.Action:UsetheDROPINDEXstatementinstead.ORA-44739是Oracle数据库中的一个错误代码。它表明，用...

IT技术学习·2023-07-28

ORA-38471: ROWIDs for table aliases cannot be null

文档解释ORA-38471:ROWIDsfortablealiasescannotbenullCause:Anattemptwasmadetopassanullvalueforthetablealiasattributeinthedataitem,whichisnotpermitted.Action:Passavali...

IT技术学习·2023-07-28

ORA-44747: An XMLIndex with a structured component cannot be specified with ASYNC.

文档解释ORA-44747:AnXMLIndexwithastructuredcomponentcannotbespecifiedwithASYNC.Cause:AnattemptwasmadetospecifyASYNCparameterforanXMLIndexwithastructuredcomponent.Ac...

IT技术学习·2023-07-28

ORA-38810: Implementation restriction: cannot drop edition that has a parent and a child

文档解释ORA-38810:Implementationrestriction:cannotdropeditionthathasaparentandachildCause:Thiserroroccurredbecauseanattemptwasmadetodropaneditionthathasaparentandac...

IT技术学习·2023-07-28

ORA-53213: cannot access DICOM data with invalid source type

文档解释ORA-53213:cannotaccessDICOMdatawithinvalidsourcetypeCause:AninvalidsourcetypewasstoredinthesourceattributeoftheORDDicomobject.Action:SeetheOracleMultimediad...

IT技术学习·2023-07-28

ORA-31048: Unsaved resources cannot be updated

文档解释ORA-31048:UnsavedresourcescannotbeupdatedCause:Anattemptwasmadetoupdatearesourcethatwasneversavedtodisk.Action:Performaresourceinsertioninstead.ORA-31048:Un...

IT技术学习·2023-07-28

ORA-27503: IPC error attempting to cancel request

文档解释ORA-27503:IPCerrorattemptingtocancelrequestCause:Thisisanoperatingsystem/clusterinterconnecterror.Action:CheckthevalueoferrnoandcontactOracleSupportServices...

IT技术学习·2023-07-28

ORA-25100: TABLESPACE option can only be used with ALTER INDEX REBUILD

文档解释ORA-25100:TABLESPACEoptioncanonlybeusedwithALTERINDEXREBUILDCause:TheTABLESPACEoptiontoALTERINDEXwasusedwithouttheREBUILDoption.Action:UseALTERINDEXREBUILDT...

IT技术学习·2023-07-28

ORA-39202: Data cannot be filtered or selected in string jobs.

文档解释ORA-39202:Datacannotbefilteredorselectedinstringjobs.Cause:Adatafilterwassuppliedforthespecifiedtypeofjob,butisnotsupportedinthespecifiedjobtype.Fromthecomm...

IT技术学习·2023-07-28

ORA-44742: Cannot alter columns of a table that is shared by other group(s).

文档解释ORA-44742:Cannotaltercolumnsofatablethatissharedbyothergroup(s).Cause:Anattemptwasmadetoaddcolumnsto,modifycolumnsof,ordropcolumnsfromatablesharedbyothergro...

IT技术学习·2023-07-28

ORA-41604: cannot revoke a privilege that was not granted

文档解释ORA-41604:cannotrevokeaprivilegethatwasnotgrantedCause:Anattemptwasmadetorevokeaprivilegethatwasnevergranted.Action:NoneORA-41604错误代表着不能撤销一个没有被授予的权限。官方解释常见案...

IT技术学习·2023-07-28