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What is a variable in C++?
Storing and retrieving data can become very complicated, and slows down the speed of a computer. To make things more efficient this task is delegated to a dedicated program, which works on a basic set of concepts. To further simplify the task for the programmer C++ allows for loose ambiguous references to the data. The reference is called a variable, and it allows for data to be stored simply by human readable language by arranging the reference of the data into types of regions known as objects which hold the unique names of the specific data that needs to be referenced. -
What is Definition of a variable?
A variable is a known specific reference to a location of data in storage, grouped in a region known as an object. -
What is Instantiation of a variable?
Instantiation takes place when the program is run, the variables of the program are managed with the storage available to establish the physical area of storage on the drive and the reference to that area. -
What is the difference between an l-value and an r-value?
Variables contain details which allow them to be used and manipulated in different ways, to control the data and errors in your program when can use different types of definitions of value to prevent the variables becoming corrupted. From a programmers perspective variables which are easy to modify allow them to be used in scaling of a program, i-value variables are such types but have the limitation of passing to other functions and can also cause programs to use unnecessary space. r-value variables have the ability to be more efficient, free space when not in use and are best for passing from function to function, inherently r-values are used on the cpu side of functions while l-types are used on the programing side of functions. -
What is an uninitialized variable and what kind of behavior can you expect from such a variable?
Uninitialized variables are variables which have been allocated a reference to a space on the storage drive but do not contain related values, itâs simply a holder that fits into a predetermined structure that the program can access and utilize at a later time. The major benefit here is that it compiling speed is very fast due to not removing data that may already be allocated in the stored area on the drive and simply only restructuring the predetermined ranges of areas the variables will reference when the variable needs to be initialized at a later time. -
What is undefined behaviour?
The benefit of an uninitialized variable was the increased speed of compiling the source code, unfortunately the disadvantage of this strategy to increase speed results in undefined behavior sometimes because the programer may not initialize the variable before it is referenced. To avoid this issue, it is best to still initialized variables once they are instantiated, thus reducing the risk of error. The major benefit of uninitialized variables can be noticed in larger data pools, were it is very challenging for the programmer to provide the data and the values for the variables on compilation, therefore C++ provides a major benefit for managing larger forms of data.
- What is a variable in C++? An Object is region of storage (usually memory) that has a value and other associated properties; Objects can be named or unnamed (anonymous), named object is called a variable, and the name of the object is called an identifier.
- What is Definition of a variable? In order to create a variable, we use a special kind of declaration statement called a definition, giving it the name and the type.
- What is Instantiation of a variable? Instantiation is a fancy word that means the object will be created and assigned a memory address. Variables must be instantiated before they can be used to store values.
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What is the difference between an l-value and an r-value?
L-value: âl-valueâ refers to memory location which identifies an object. l-value may appear as either left hand or right hand side of an assignment operator(=). l-value often represents as identifier.
R-value : r-valueâ refers to data value that is stored at some address in memory. A r-value is an expression that canât have a value assigned to it which means r-value can appear on right but not on left hand side of an assignment operator(=). - What is an uninitialized variable and what kind of behaviour can you expect from such a variable? In computing, an uninitialized variable is a variable that is declared but is not set to a definite known value before it is used. It will have some value, but not a predictable one. As such, it is a programming error and a common source of bugs in software.
- What is undefined behaviour? In computer programming, undefined behavior is the result of executing computer code whose behavior is not prescribed by the language specification to which the code adheres, for the current state of the program. This happens when the translator of the source code makes certain assumptions, but these assumptions are not satisfied during execution.
Reading Assignment - Variables in C++
- What is a variable in C++? A variable is a object which has a name.
- What is Definition of a variable? A variable must be defined with name ("example") and a data type ("int" for integer)
- What is Instantiation of a variable?
- What is the difference between an I-value and an r-value? While an I-value has a persistent address, a r-value hasn't.
- What is an uninitialized variable and what kind of behavior can you expect from such a variable? An uninitialized variable is in memory but it doesn't have a value assigned to it. That can cause unexpected behavior
- What is undefined behavior? An undefined behavior is when a program works fine in the first few attempts and suddenly produces different outputs.
int example; // a variable called "example" is defined as an integer
While a program is running variables will be instantiated. It means that the variables will get assigned to a memory address as an object.
- A variable is a named object.
- The definition of a variable is a named region of memory.
- The instantiation of a variable means the object will created and assigned a memory address.
- An l-value represents an object that occupies some identifiable location in memory, an r-value is an expression that does not represent an object occupying some identifiable location in memory.
- An uninitialized variable is a variable that has not been given a known value (usually through initialization or assignment).
- An undefined behavior is the result of executing code whose behavior is not well defined by the language.
#letsgetthiscrypto
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What is a variable in C++?
An object with a name -
What is Definition of a variable?
Giving a type and name to a variable -
What is Instantiation of a variable?
Taking defined variable and putting it into memory -
What is the difference between an l-value and an r-value?
l-value can be left or right of =
r-value can only be on right side of = -
What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
Canât find it in memory -
What is undefined behaviour?
Unexpected code behavior
- A variable is an object with a name.
- A declaration statement in order to create a variable. Each variable needs a type.
- Instantiation is when a piece of memory from the RAM will be set aside when the statement is executed by the CPU.
- I-value have a persistent adress in memory. R-value are temporary.
- Uninitialized variable has not been given a value but has been defined.
- Undefined behavior happens when code is executed but not well defined by the language.
- What is a variable in C++?
A : Named object is called a variable, In C++, the term object has a narrower definition that excludes functions.
- What is Instantiation of a variable?
A: Instantiation is a fancy word that means the object will be created and assigned a memory address. An instantiated object is sometimes also called an instance.
- What is the difference between an l-value and an r-value?
A: An l-value is an expression that refers to such an object. The original definition of an l-value was âan object that can appear on the left-hand side of an assignmentâ. ⌠In this case, the l-value is implicitly converted to an r-value. However, you cannot place an r-value in a context that requires an l-value.
- What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
A: An uninitialized variable is a variable that is declared but is not set to a definite known value before it is used. It will have some value, but not a predictable one. As such, it is a programming error and a common source of bugs in software.
- What is undefined behaviour?
A: Many programmers know that certain behaviors in C/C++ are âundefinedâ. Undefined behaviors include common bugs like NULL dereference or signed integer overflow. ⌠The C99 standard alone defines 191 undefined behaviors. The chances are that your code exhibits undefined behavior.
- What is a variable in C++?
A named memory location that contains a value
- What is Definition of a variable?
The type of data that can be stored in the variable
- What is Instantiation of a variable?
Instantiation is when a variable is created (assigned a memory location) at run-time
- What is the difference between an l-value and an r-value?
R-value is a value that is stored in a temporary memory location that can not be changed. This is the right side of an equation. L-value can be on either the left or right side of an equation; values on the left are modifiable l-values.
- What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
Uninitialized variable is one that has been declared but not assigned a value. Referencing this variable will create errors and/or inconsistent results.
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What is undefined behaviour?
Undefined behaviour involved having no restrictions on the behavior of the program. Examples of undefined behavior are memory accesses outside of array bounds, signed integer overflow, null pointer dereference, modification of the same scalar [more than once] in an expression without sequence points, access to an object through a pointer of a different type, etc.
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What is a variable in C++?
An object which the compiler will use to give it a place in memory -
What is Definition of a variable?
A named region of memory. -
What is Instantiation of a variable?
that means the object will be created and assigned a memory address -
What is the difference between an l-value and an r-value?
l-values have their place in memory, r-values are values are discarded at the end of a statement and therefore need not to be associated with a memory address -
What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
a declared variable whose value in the memory address has not yet been initialized. using such variables can lead to undefined behaviour -
What is undefined behaviour?
the result of executing code whose behavior is not well defined by the language.
- What is a variable in C++?
It is named region of the storage that can store a data value.
- What is Definition of a variable?
It is special kind of declaration statement.
- What is Instantiation of a variable?
It means creating and assigning object to the memory address.
- What is the difference between an l-value and an r-value?
There is no information in the text about it, after reading comments I guess it is something like this:
int x {33}; // it is ok or
int y = 12;
9 = int z; // it is not allowed what is quite obvious
- What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
Variable without given value and it can cause undefined behaviour.
- What is undefined behaviour?
It is the result of executing code whose behavior is not well defined by the C++ language.
Code implementing undefined behavior may exhibit any of the following symptoms:
- Your program produces different results every time it is run.
- Your program consistently produces the same incorrect result.
- Your program behaves inconsistently (sometimes produces the correct result, sometimes not).
- Your program seems like its working but produces incorrect results later in the program.
- Your program crashes, either immediately or later.
- Your program works on some compilers but not others.
- Your program works until you change some other seemingly unrelated code.
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What is a variable in C++?
A named object . -
What is Definition of a variable?
a special kind of declaration statement -
What is Instantiation of a variable?
Create and assign a memory address -
What is the difference between an l-value and an r-value?
l-values (the only values allowed on the left side of an expression) are values that have a memory address. -
What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
An uninitialized variable is a variable that has not been given a known value. If it is used, it will produce whatever value is present at its memory location. -
What is undefined behavior?
It is the result of executing code whose behavior is not defined by the language.
1.What is a variable in C++?
a named object
2.What is Definition of a variable?
a special kind of declaration for a variable, for example int x; so we have a variable x that can hold an integer value
3.What is Instantiation of a variable?
the âreservationâ of memory in RAM for a variable
4.What is the difference between an l-value and an r-value?
l-values are values that have their place in memory, r-values are values (or expressions) that are discarded at the end of a statement and therefore need not to be associated with a memory address
5.What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
a declared variable whose value in the memory address has not yet been initialized. using such variables can lead to undefined behaviour
6.What is undefined behaviour?
Undefined behavior is the result of executing code whose behavior is not well defined by the language.
- What is a variable in C++?
Any text that represents a value.
- What is Definition of a variable?
A named object with a pointer to a memory location in RAM.
- What is Instantiation of a variable?
After declaration of a variable, you give it a value. Uninitialized variables can produce unpredictable results. It can point to a previously used location in memory that was previously freed.
- What is the difference between an l-value and an r-value?
Some values can result from code execution and are temporary in nature, whereas other values are the result of declaration and initialization.
- What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
An uninitialized variable points to some location in memory that will have whatever was previously there.
- What is undefined behaviour?
Usually the result of uninitialized variables or a function that has no return value because of a mistake in program logic.
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A variable in C++ is a named object, which can store a data value.
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What is Definition of a variable?
Defining the variable with a name and the type of data (int, double,float,âŚ) -
What is Instantiation of a variable?
The object will be created and assigned a memory address. -
What is the difference between an l-value and an r-value?
l-value can only be a value that has a persistent address and only be on the left hand side of an assignment statement. r-value are values that are not associated with a persistent statement and only be on the right hand side of an assignment statement. -
What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
An uninitialized variable is an used variable without a know value. This will lead to an undefined behavior. Maybe the programm can´t be compiled, maybe the value will be assigned to a random memory with a reasonable value and you will get sometimes the right output. â âWho knows!ââ -
What is undefined behaviour?
An undefined behavior is a result of executing code whose behavior is not well defined. There are no rules how to treat the running code, so the result is always different, always wrong, crashes or is only working on some compilers.
â Always initialize all variables, objects!!
- A variable in C++ is an object that gets stored in the computers memory.
- A definition of a variable is a statement telling C++ what kind of information will be stored.
- Its a place where our variable will be stored at.
- An I-value it a value that stays in the memory while R-value is the value that is only used in computing to help us get the new I-value.
- An uninitialized variable is a defined variable without any information.and if called my appear as having some other random data we donât want, causing bugs and problems.
- Undefined behavior is the result of executing a code that does not provide correct outputs all the time.Using an uninitialized value can lead to an undefined behavior as the value of such a variable can always be different which may cause the program to sometimes work and sometimes not.
- What is a variable in C++?
A named object that stores values
- What is Definition of a variable?
Specifying a type and a name for a variable for example. For example int x; so we have a variable x that can hold an integer value
- What is Instantiation of a variable?
int is to store the variable as a object in the RAM or memory of the computer
- What is the difference between an l-value and an r-value?
l-value has-persistent address & r-value is not associated with a persistent memory address.
- What is an uninitialized variable and what kind of behaviour can you expect from such a variable?
A variable that has not been given a value is called uninitialized. The usage of such a variable leads to unpredictable results as itâs value is being taken from the memory location it has been alocated to.
- What is undefined behaviour?
Unpredictable behaviour resulting from the use of uninitialised variables, because C++ has no rules determining what happens.
What is a variable in C++?
A variable in C++ is a named object
What is Definition of a variable?
A variable is a name used to identify a particular object, keep in mind âIn general programming, the term object typically refers to a variable, data structure in memory, or function. In C++, the term object has a narrower definition that excludes functions.â
What is Instantiation of a variable?
âInstantiation is a fancy word that means the [named] object will be created and assigned a memory address.â
Because the object is named, it is a variable.
What is the difference between an l-value and an r-value?
An I-value points to a specific location in memory, where an r-value does not and would need to be assigned to a variable to be stored.
What is an uninitialized variable and what kind of behavior can you expect from such a variable?
An uninitialized variable is a variable that has been assigned, but the value has yet to be defined.
What is undefined behavior?
Undefined behavior is when a program operates and produces an output without working within the definitions of the programming language.
Even if a program containing undefined behavior functions as in intended, undefined behavior can cause issue in debugging later. This is different than a program that produces defined errors but still operates.
- A named object is called a variable.
- For example: int x; // define a variable named x, of type int
- It means the object will be created and assigned a memory address. Variables must be instantiated before they can be used to store values.
- l-value has-persistent address & r-value is not associated with a persistent memory address.
- Is a variable that has not been given a known value; the behavior you can expect to see is your compiler will assign a random space in the memory which can change every time you run and compile the code.
- The resulting value of an uninitialized variable.