Java – FileReader Class. Advertisements. This class inherits from the InputStreamReader class. FileReader is used for reading streams of characters. This class has several constructors to create required objects.
Likewise, what is the use of InputStreamReader and BufferedReader in Java?
InputStreamReader creates a new stream object that can be used to read data from the specified source. It reads bytes and decodes them into characters. BufferedReader is an “abstraction” that reads text from a character-input stream. It “buffers” characters so as to provide efficient reading of characters and lines.
Why BufferedReader is faster than scanner?
The Scanner has a little buffer (1KB char buffer) as opposed to the BufferedReader (8KB byte buffer), but it’s more than enough. BufferedReader is a bit faster as compared to scanner because scanner does parsing of input data and BufferedReader simply reads sequence of characters.
What is file and example?
A file is an object on a computer that stores data, information, settings, or commands used with a computer program. For example, the picture is an icon associated with Adobe Acrobat PDF files.
What is type def?
typedef is a reserved keyword in the C and C++ programming languages. It is used to create an alias name for another data type.
What is the use of typedef?
The typedef keyword allows the programmer to create new names for types such as int or, more commonly in C++, templated types–it literally stands for “type definition”. Typedefs can be used both to provide more clarity to your code and to make it easier to make changes to the underlying data types that you use.
What do you mean by lvalue and rvalue?
An lvalue refers to an object that persists beyond a single expression. You can think of an lvalue as an object that has a name. All variables, including nonmodifiable ( const ) variables, are lvalues. An rvalue is a temporary value that does not persist beyond the expression that uses it.
What does Lvalue stand for?
An lvalue is a value that can be assigned to: lvalue = rvalue; It’s short for “left value” or “lefthand value” and it’s basically just the value on the left of the = sign, i.e. the value you assign something to.
What is an rvalue reference?
An rvalue reference is a compound type very similar to C++’s traditional reference. To better distinguish these two types, we refer to a traditional C++ reference as an lvalue reference. When the term reference is used, it refers to both kinds of reference: lvalue reference and rvalue reference.
What is L value required?
An “lvalue” is a value that can be the target of an assignment. The “l” stands for “left”, as in the left hand side of the equals sign. If you are getting “lvalue required” you have an expression that produces an rvalue when an lvalue is required. For example, a constant is an rvalue but not an lvalue.
What is the meaning of lvalue required in C language?
The lvalue required error is primarily due to wrong implementation of the assignment/equal to operator. The rvalue is computed and assigned to lvalue. a + b = c is wrong because it is not possible to assign the value of c to a + b.
What is Lvalue error in Turbo C++?
The assignment is trying to change the value of an integer constant. Fortunately, C and C++ compilers reject it as an error. The C++ Standard does use the term rvalue, defining it indirectly with this sentence: “Every expression is either an lvalue or an rvalue.” So an rvalue is any expression that is not an lvalue.
What does a typedef do?
From Wikipedia: typedef is a keyword in the C and C++ programming languages. It is used to give a data type a new name. The intent is to make it easier for programmers to comprehend source code.
How a pointer is initialized?
Initialization of Pointer variable. Pointer variable can only contain address of a variable of the same data type. In C language address operator & is used to determine the address of a variable. The & (immediately preceding a variable name) returns the address of the variable associated with it.
What does memcpy do?
The memcpy function is used to copy a block of data from a source address to a destination address. void * memcpy(void * destination, const void * source, size_t num); The idea is to simply typecast given addresses to char *(char takes 1 byte).
Can void pointers be dereferenced?
You have a pointer to a single int , not two. That dereference causes undefined behavior. A void pointer is just that, a pointer to a void (nothing definable). For example malloc() returns a void pointer precisely because it allocated memory for an UNDEFINED purpose.
What is the use of void pointers?
-> void pointers in C are used to implement generic functions in C. For example comparator in qsort(). But it can’t be dereferenced without type casting to a data type. Originally Answered: What is the usage of a void pointer? A void pointer can be a pointer to ‘anything’, meaning any other type.
What does void *?
A pointer to void is a “generic” pointer type. A void * can be converted to any other pointer type without an explicit cast. You cannot dereference a void * or do pointer arithmetic with it; you must convert it to a pointer to an complete data type first.