get out cast

This article from: http://blog.csdn.net/xuejianwu/article/details/6931926X. Conversion operatorsConversion operators are used to implement the ability to convert the type of an input object into a sequence. The conversion method whose name starts with "as" changes the static type of the source collection but does not enumerate (lazy-load) this source collection. The method that begins with the name "to" enumerates the source collection and puts the items into the appropriate collection type.1. A

warning:unchecked cast from object to array listThis address: Http://blog.csdn.net/caroline_wendyA warning occurs when an object is cast to an array (ArrayList) type, such as:Infos = (arraylistbecause an object is converted to an array type, it is not checked for a certain risk.causes the array object to be cast, asArraylistHowever, in order to write simple and

hand. If downcast and the type parameter is not polymorphic, dynamic_cast cannot be used and the compiler will give an error.dynamic_cast returns a null pointer if the type of the object is not the base class of the type that will be converted to. That is, a non-derived class object is converted to a base class object, or a base class object is converted to a derived class object, returning a null pointer.#include In this example, the base class object is converted to a derived class object and

Recently, when using JSON, the following error was reported:Net.sf.ezmorph.bean.MorphDynaBean cannot is cast to java.lang.StringThis error is common because JSON is converted to JavaBean by default to the Morphdynabean class. As in the following example:When the JSON string is JavaBean, the general object can be transferred directly, such as: A student class, the attribute has the name, the age and so on. Public classStudentImplementsjava.io.serializa

Convert to Numericnumber function cast to numeric value Value --Convert to originalstring -if it can be resolved to a numeric value, convert to a numeric value; otherwise convert to NaN or 0True->1,false->0Undefined->nanNull->0Convert to integral typePraseint ()Convert to floating point typePrasefloat ()Attentionthe number function is much stricter than the Praseint function to convert a string to a numeric value . Basically, as long as one character

Apple app support Arm64 there will be a problem: Nsinteger becomes 64 bits, and the original int (%d) does not match, will be reported as follows warning,Values of type ' nsinteger ' should not being used as format arguments; Add an explicit cast to ' long ' insteadWorkaround:0,Nsinteger number = 0;NSString *str = [NSString stringwithformat:@ "%d", number]; If number is enough for 32 bits,0, you can change the number is defined as int # = 0; 1

An error occurs during compilation: Error: cast from 'Char * 'to 'int' loses precision Cause: the program exists. Char * addrCom; addrCom =... // assign the value if (-1 = (int) addrCom) // causes a compilation error {......} The above is implicit conversion. Change it to Standard C ++ display type conversion: static_cast Still: Error: cast from 'Char * 'to 'int' loses precision Finally google a

The only reason to watch this movie is to confirm a friend's movie rating. If the story of "name cast" is simply summarized as follows: the three brothers of the Covenant should do big things in the autumn of chaos, but B's loyalty to thin clouds is calculated and destroyed by, c. Discover the truth and. Oh, yes, this is the late Qing Dynasty version of the "bloody streets" Jin chengwu has been playing a big-name supporting role in large movies this

Cast and convert explicitly convert a certain data type expression to another data type. Cast and convert provide similar functions. Syntax CAST expressionAS data_type CONVERT (data_type[(length)]， expression [， style]) Parameter expression Is any valid Microsoft SQL Server expression. For more information, see. Data_type The data types provided by the target s

1. Cast Cast (data as data_type) Example: declare @ data int Set @ DATA = 5 Select cast (@ data as char (2) + 'abc' -- Result: 5 ABC 2. Convert Convert (data_type, expresses (, style) -- style is the style of the specified date Select convert (varchar, getdate (), 120)-- 15:10:02 Select Replace (replace (convert (varchar, getdate (), 120

Inconvertible types; Cannot cast ' android.supoort.v4.app.Fragment ' to ' com.example.sevenun.littledemo.fragment.NewsTitleFragment 'Inconvertible types; Cannot cast ' android.app.Fragment ' to ' com.example.sevenun.littledemo.fragment.NewsTitleFragment 'The above error occurred because we imported android.supoort.v4.app.Fragment in some classes and android.app.Fragment in some classes.In fact, these two ca

Double Forcing data type conversionsThe format of the cast is to add "()" before the data that needs to be transformed, and then add the data type that needs to be converted in parentheses. Some data after transformation operation, the accuracy will be lost, and some will be more accurate, the following example can illustrate this problem. Public class Demo { public static void main(String[] args){ int x; double y

;double Note: Long is 8 bytes and float is 4 bytes. A long is an integer, float is a floating-point type, and an integer is not stored with a floating-point number, and remember that a long range is less than float. Cases: BYTE a=10;int b=a; When Intb=a is compiled, a is implicitly converted to type int. Forced conversions Characteristics: From big to small (if you know explicitly that data can be represented by that data type, you can use a cast