单片机error C183: unmodifiable lvalue

云荒只如初见 2012-12-30 09:12:27
union
{ unsigned int i;
float f;
}humi_val,temp_val; //定义两个共同体，一个用于湿度，一个用于温度

disp[0]=&humi_val.f%16;
disp[1]=&humi_val.f/16;
这个怎么修改啊？
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shinerise 2012-12-31
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为什么用存储地址去%16？另外浮点数取余的结果是什么？还从来没试过。
AnYidan 2012-12-31
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引用 2 楼 woshi_ziyu 的回复:
浮点数求余要用库函数fmod，在math.h里面
++ 但任何数据类型的地址都是 int
Yingyingzi000 2012-12-31
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单片机，至少keil不支持单精度float，只能用double。 小吐一下槽，double的运算是相当费CPU的。 还有，取余以后要转化整数 例如：disp[0]=(int)(humi_val.f%16); 前面加&取地址实在是不知道你想干什么……
woshi_ziyu 2012-12-31
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浮点数求余要用库函数fmod，在math.h里面
关于C语言中类型限定符const的研究.pdf
关于C语言中类型限定符const的研究.pdf
struts_2.3.12GA_API文档(chm版本)
-------------------------------------------------------------------------------- 概述 软件包 类 使用 树 已过时 索引 帮助 上一个类 下一个类 框架 无框架 所有类 摘要： 嵌套 | 字段 | 构造方法 | 方法 详细信息： 字段 | 构造方法 | 方法 -------------------------------------------------------------------------------- com.opensymphony.xwork2 类 ActionSupport java.lang.Object 继承者 com.opensymphony.xwork2.ActionSupport 所有已实现的接口： Action, LocaleProvider, TextProvider, Validateable, ValidationAware, Serializable 直接已知子类： DefaultActionSupport -------------------------------------------------------------------------------- public class ActionSupportextends Objectimplements Action, Validateable, ValidationAware, TextProvider, LocaleProvider, SerializableProvides a default implementation for the most common actions. See the documentation for all the interfaces this class implements for more detailed information. 另请参见： 序列化表格 -------------------------------------------------------------------------------- 字段摘要 从接口 com.opensymphony.xwork2.Action 继承的字段 ERROR, INPUT, LOGIN, NONE, SUCCESS 构造方法摘要 ActionSupport() 方法摘要 void addActionError(String anErrorMessage) Add an Action-level error message to this Action. void addActionMessage(String aMessage) Add an Action-level message to this Action. void addFieldError(String fieldName, String errorMessage) Add an error message for a given field. void clearActionErrors() Clears action errors. void clearErrors() Clears all errors. void clearErrorsAndMessages() Clears all errors and messages. void clearFieldErrors() Clears field errors. void clearMessages() Clears messages. Object clone() String doDefault() String execute() A default implementation that does nothing an returns "success". Collection getActionErrors() Get the Collection of Action-level error messages for this action. Collection getActionMessages() Get the Collection of Action-level messages for this action. Collection getErrorMessages() 已过时。 Use getActionErrors(). Map> getErrors() 已过时。 Use getFieldErrors(). Map> getFieldErrors() Get the field specific errors associated with this action. String getFormatted(String key, String expr) Dedicated method to support I10N and conversion errors Locale getLocale() Gets the provided locale. String getText(String aTextName) Gets a message based on a message key, or null if no message is found. String getText(String aTextName, List<?> args) Gets a message based on a key using the supplied args, as defined in MessageFormat, or null if no message is found. String getText(String aTextName, String defaultValue) Gets a message based on a key, or, if the message is not found, a supplied default value is returned. String getText(String key, String[] args) Gets a message based on a key using the supplied args, as defined in MessageFormat, or null if no message is found. String getText(String aTextName, String defaultValue, List<?> args) Gets a message based on a key using the supplied args, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. String getText(String key, String defaultValue, List<?> args, ValueStack stack) Gets a message based on a key using the supplied args, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. String getText(String aTextName, String defaultValue, String obj) Gets a message based on a key using the supplied obj, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. String getText(String key, String defaultValue, String[] args) Gets a message based on a key using the supplied args, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. String getText(String key, String defaultValue, String[] args, ValueStack stack) Gets a message based on a key using the supplied args, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. ResourceBundle getTexts() Get the resource bundle associated with the implementing class (usually an action). ResourceBundle getTexts(String aBundleName) Get the named bundle, such as "com/acme/Foo". boolean hasActionErrors() Check whether there are any Action-level error messages. boolean hasActionMessages() Checks whether there are any Action-level messages. boolean hasErrors() Checks whether there are any action errors or field errors. boolean hasFieldErrors() Check whether there are any field errors associated with this action. boolean hasKey(String key) Checks if a message key exists. String input() void pause(String result) Stops the action invocation immediately (by throwing a PauseException) and causes the action invocation to return the specified result, such as Action.SUCCESS, Action.INPUT, etc. void setActionErrors(Collection errorMessages) Set the Collection of Action-level String error messages. void setActionMessages(Collection messages) Set the Collection of Action-level String messages (not errors). void setContainer(Container container) void setFieldErrors(Map> errorMap) Set the field error map of fieldname (String) to Collection of String error messages. void validate() A default implementation that validates nothing. 从类 java.lang.Object 继承的方法 equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait 构造方法详细信息 ActionSupport public ActionSupport()方法详细信息 setActionErrors public void setActionErrors(Collection errorMessages)从接口 ValidationAware 复制的描述 Set the Collection of Action-level String error messages. 指定者： 接口 ValidationAware 中的 setActionErrors 参数： errorMessages - Collection of String error messages -------------------------------------------------------------------------------- getActionErrors public Collection getActionErrors()从接口 ValidationAware 复制的描述 Get the Collection of Action-level error messages for this action. Error messages should not be added directly here, as implementations are free to return a new Collection or an Unmodifiable Collection. 指定者： 接口 ValidationAware 中的 getActionErrors 返回： Collection of String error messages -------------------------------------------------------------------------------- setActionMessages public void setActionMessages(Collection messages)从接口 ValidationAware 复制的描述 Set the Collection of Action-level String messages (not errors). 指定者： 接口 ValidationAware 中的 setActionMessages 参数： messages - Collection of String messages (not errors). -------------------------------------------------------------------------------- getActionMessages public Collection getActionMessages()从接口 ValidationAware 复制的描述 Get the Collection of Action-level messages for this action. Messages should not be added directly here, as implementations are free to return a new Collection or an Unmodifiable Collection. 指定者： 接口 ValidationAware 中的 getActionMessages 返回： Collection of String messages -------------------------------------------------------------------------------- getErrorMessages @Deprecated public Collection getErrorMessages()已过时。 Use getActionErrors(). -------------------------------------------------------------------------------- getErrors @Deprecated public Map> getErrors()已过时。 Use getFieldErrors(). -------------------------------------------------------------------------------- setFieldErrors public void setFieldErrors(Map> errorMap)从接口 ValidationAware 复制的描述 Set the field error map of fieldname (String) to Collection of String error messages. 指定者： 接口 ValidationAware 中的 setFieldErrors 参数： errorMap - field error map -------------------------------------------------------------------------------- getFieldErrors public Map> getFieldErrors()从接口 ValidationAware 复制的描述 Get the field specific errors associated with this action. Error messages should not be added directly here, as implementations are free to return a new Collection or an Unmodifiable Collection. 指定者： 接口 ValidationAware 中的 getFieldErrors 返回： Map with errors mapped from fieldname (String) to Collection of String error messages -------------------------------------------------------------------------------- getLocale public Locale getLocale()从接口 LocaleProvider 复制的描述 Gets the provided locale. 指定者： 接口 LocaleProvider 中的 getLocale 返回： the locale. -------------------------------------------------------------------------------- hasKey public boolean hasKey(String key)从接口 TextProvider 复制的描述 Checks if a message key exists. 指定者： 接口 TextProvider 中的 hasKey 参数： key - message key to check for 返回： boolean true if key exists, false otherwise. -------------------------------------------------------------------------------- getText public String getText(String aTextName)从接口 TextProvider 复制的描述 Gets a message based on a message key, or null if no message is found. 指定者： 接口 TextProvider 中的 getText 参数： aTextName - the resource bundle key that is to be searched for 返回： the message as found in the resource bundle, or null if none is found. -------------------------------------------------------------------------------- getText public String getText(String aTextName, String defaultValue)从接口 TextProvider 复制的描述 Gets a message based on a key, or, if the message is not found, a supplied default value is returned. 指定者： 接口 TextProvider 中的 getText 参数： aTextName - the resource bundle key that is to be searched for defaultValue - the default value which will be returned if no message is found 返回： the message as found in the resource bundle, or defaultValue if none is found -------------------------------------------------------------------------------- getText public String getText(String aTextName, String defaultValue, String obj)从接口 TextProvider 复制的描述 Gets a message based on a key using the supplied obj, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. 指定者： 接口 TextProvider 中的 getText 参数： aTextName - the resource bundle key that is to be searched for defaultValue - the default value which will be returned if no message is found obj - obj to be used in a MessageFormat message 返回： the message as found in the resource bundle, or defaultValue if none is found -------------------------------------------------------------------------------- getText public String getText(String aTextName, List<?> args)从接口 TextProvider 复制的描述 Gets a message based on a key using the supplied args, as defined in MessageFormat, or null if no message is found. 指定者： 接口 TextProvider 中的 getText 参数： aTextName - the resource bundle key that is to be searched for args - a list args to be used in a MessageFormat message 返回： the message as found in the resource bundle, or null if none is found. -------------------------------------------------------------------------------- getText public String getText(String key, String[] args)从接口 TextProvider 复制的描述 Gets a message based on a key using the supplied args, as defined in MessageFormat, or null if no message is found. 指定者： 接口 TextProvider 中的 getText 参数： key - the resource bundle key that is to be searched for args - an array args to be used in a MessageFormat message 返回： the message as found in the resource bundle, or null if none is found. -------------------------------------------------------------------------------- getText public String getText(String aTextName, String defaultValue, List<?> args)从接口 TextProvider 复制的描述 Gets a message based on a key using the supplied args, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. 指定者： 接口 TextProvider 中的 getText 参数： aTextName - the resource bundle key that is to be searched for defaultValue - the default value which will be returned if no message is found args - a list args to be used in a MessageFormat message 返回： the message as found in the resource bundle, or defaultValue if none is found -------------------------------------------------------------------------------- getText public String getText(String key, String defaultValue, String[] args)从接口 TextProvider 复制的描述 Gets a message based on a key using the supplied args, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. 指定者： 接口 TextProvider 中的 getText 参数： key - the resource bundle key that is to be searched for defaultValue - the default value which will be returned if no message is found args - an array args to be used in a MessageFormat message 返回： the message as found in the resource bundle, or defaultValue if none is found -------------------------------------------------------------------------------- getText public String getText(String key, String defaultValue, List<?> args, ValueStack stack)从接口 TextProvider 复制的描述 Gets a message based on a key using the supplied args, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. Instead of using the value stack in the ActionContext this version of the getText() method uses the provided value stack. 指定者： 接口 TextProvider 中的 getText 参数： key - the resource bundle key that is to be searched for defaultValue - the default value which will be returned if no message is found args - a list args to be used in a MessageFormat message stack - the value stack to use for finding the text 返回： the message as found in the resource bundle, or defaultValue if none is found -------------------------------------------------------------------------------- getText public String getText(String key, String defaultValue, String[] args, ValueStack stack)从接口 TextProvider 复制的描述 Gets a message based on a key using the supplied args, as defined in MessageFormat, or, if the message is not found, a supplied default value is returned. Instead of using the value stack in the ActionContext this version of the getText() method uses the provided value stack. 指定者： 接口 TextProvider 中的 getText 参数： key - the resource bundle key that is to be searched for defaultValue - the default value which will be returned if no message is found args - an array args to be used in a MessageFormat message stack - the value stack to use for finding the text 返回： the message as found in the resource bundle, or defaultValue if none is found -------------------------------------------------------------------------------- getFormatted public String getFormatted(String key, String expr)Dedicated method to support I10N and conversion errors 参数： key - message which contains formatting string expr - that should be formatted 返回： formatted expr with format specified by key -------------------------------------------------------------------------------- getTexts public ResourceBundle getTexts()从接口 TextProvider 复制的描述 Get the resource bundle associated with the implementing class (usually an action). 指定者： 接口 TextProvider 中的 getTexts 返回： the bundle -------------------------------------------------------------------------------- getTexts public ResourceBundle getTexts(String aBundleName)从接口 TextProvider 复制的描述 Get the named bundle, such as "com/acme/Foo". 指定者： 接口 TextProvider 中的 getTexts 参数： aBundleName - the name of the resource bundle, such as "com/acme/Foo". 返回： the bundle -------------------------------------------------------------------------------- addActionError public void addActionError(String anErrorMessage)从接口 ValidationAware 复制的描述 Add an Action-level error message to this Action. 指定者： 接口 ValidationAware 中的 addActionError 参数： anErrorMessage - the error message -------------------------------------------------------------------------------- addActionMessage public void addActionMessage(String aMessage)从接口 ValidationAware 复制的描述 Add an Action-level message to this Action. 指定者： 接口 ValidationAware 中的 addActionMessage 参数： aMessage - the message -------------------------------------------------------------------------------- addFieldError public void addFieldError(String fieldName, String errorMessage)从接口 ValidationAware 复制的描述 Add an error message for a given field. 指定者： 接口 ValidationAware 中的 addFieldError 参数： fieldName - name of field errorMessage - the error message -------------------------------------------------------------------------------- input public String input() throws Exception抛出： Exception -------------------------------------------------------------------------------- doDefault public String doDefault() throws Exception抛出： Exception -------------------------------------------------------------------------------- execute public String execute() throws ExceptionA default implementation that does nothing an returns "success". Subclasses should override this method to provide their business logic. See also Action.execute(). 指定者： 接口 Action 中的 execute 返回： returns Action.SUCCESS 抛出： Exception - can be thrown by subclasses. -------------------------------------------------------------------------------- hasActionErrors public boolean hasActionErrors()从接口 ValidationAware 复制的描述 Check whether there are any Action-level error messages. 指定者： 接口 ValidationAware 中的 hasActionErrors 返回： true if any Action-level error messages have been registered -------------------------------------------------------------------------------- hasActionMessages public boolean hasActionMessages()从接口 ValidationAware 复制的描述 Checks whether there are any Action-level messages. 指定者： 接口 ValidationAware 中的 hasActionMessages 返回： true if any Action-level messages have been registered -------------------------------------------------------------------------------- hasErrors public boolean hasErrors()从接口 ValidationAware 复制的描述 Checks whether there are any action errors or field errors. Note: that this does not have the same meaning as in WW 1.x. 指定者： 接口 ValidationAware 中的 hasErrors 返回： (hasActionErrors() || hasFieldErrors()) -------------------------------------------------------------------------------- hasFieldErrors public boolean hasFieldErrors()从接口 ValidationAware 复制的描述 Check whether there are any field errors associated with this action. 指定者： 接口 ValidationAware 中的 hasFieldErrors 返回： whether there are any field errors -------------------------------------------------------------------------------- clearFieldErrors public void clearFieldErrors()Clears field errors. Useful for Continuations and other situations where you might want to clear parts of the state on the same action. -------------------------------------------------------------------------------- clearActionErrors public void clearActionErrors()Clears action errors. Useful for Continuations and other situations where you might want to clear parts of the state on the same action. -------------------------------------------------------------------------------- clearMessages public void clearMessages()Clears messages. Useful for Continuations and other situations where you might want to clear parts of the state on the same action. -------------------------------------------------------------------------------- clearErrors public void clearErrors()Clears all errors. Useful for Continuations and other situations where you might want to clear parts of the state on the same action. -------------------------------------------------------------------------------- clearErrorsAndMessages public void clearErrorsAndMessages()Clears all errors and messages. Useful for Continuations and other situations where you might want to clear parts of the state on the same action. -------------------------------------------------------------------------------- validate public void validate()A default implementation that validates nothing. Subclasses should override this method to provide validations. 指定者： 接口 Validateable 中的 validate -------------------------------------------------------------------------------- clone public Object clone() throws CloneNotSupportedException覆盖： 类 Object 中的 clone 抛出： CloneNotSupportedException -------------------------------------------------------------------------------- pause public void pause(String result)Stops the action invocation immediately (by throwing a PauseException) and causes the action invocation to return the specified result, such as Action.SUCCESS, Action.INPUT, etc. The next time this action is invoked (and using the same continuation ID), the method will resume immediately after where this method was called, with the entire call stack in the execute method restored. Note: this method can only be called within the execute() method. 参数： result - the result to return - the same type of return value in the execute() method. -------------------------------------------------------------------------------- setContainer public void setContainer(Container container) -------------------------------------------------------------------------------- 概述 软件包 类 使用 树 已过时 索引 帮助 上一个类 下一个类 框架 无框架 所有类 摘要： 嵌套 | 字段 | 构造方法 | 方法 详细信息： 字段 | 构造方法 | 方法 --------------------------------------------------------------------------------
有关Java编程方面的几点解惑
How well do you really know Java? Are you a code sleuth? Have you ever spent days chasing a bug caused by a trap or pitfall in Java or its libraries? Do you like brainteasers? Then this is the book for you!
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NULL 博文链接：https://futeng.iteye.com/blog/1833449
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