Variables in C++ - Reading Assignment

C++ Programming
#586

  1. What is a variable in C++?
    A variable is an object, that can be used in code at anytime depending on the scope. Without knowing what the exact value of the variable will be, variables can change and be updated throughout the code and is much better than using hard coded values.

  2. What is the Definition of a variable?
    When you declare the variable with its name and its type

  3. What is Instantiation of a variable?
    When you assign a value to the variable

  4. What is the difference between an l-value and an r-value?
    I-value represent the location in memory where the variable is stored. r value does not have an address in memory

  5. What is an uninitialized variable and what kind of behavior can you expect from such a variable? It can make the program behave unpredictably often cause errors or memory problems.

  6. What is undefined behavior?
    An example of undefined behavior is when you don’t properly initialize variables and the code behaves unpredictably. Behaving in such a way as not defined in code.

1 Like
#587

  1. What is a variable in C++?
    - A named object - Data structure in memory.

  2. What is Definition of a variable?
    - A named region of storage that can store a data value.

  3. What is Instantiation of a variable?
    - When an object is created and assigned a memory address.

  4. What is the difference between an l-value and an r-value?
    - An l-value always has a defined region of storage, so you can take its address.
    - An r-value is any expression that has a value, but cannot have a value assigned to it.

  5. 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 value by the program.

  6. What is undefined behaviour?
    - The result of executing a program whose behavior is prescribed to be unpredictable,
    in the language specification to which the computer code adheres.

1 Like
#588
  1. A variable is a named Object.
  2. Variables are containers for storing data values.
  3. “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.”
  4. I- value is an object reference and an R- value is a value. An I- value always has a defined region of storage, so you can take its address. An R- value is an expression that is not an I-value.
  5. An uninitialized variable is a variable that has not been given a value by the program.
  6. Using the value stored in an uninitialized variable will result in undefined behavior.
1 Like
#589
  1. An object with a name, can store a value.
  2. A declaration statement used in order to create a variable.
  3. Creating and assigning a memory address to an object.
    4.An l-value has a persistent address. An r-value doesn’t have a persistent address.
    5.It 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.
    6.The result of executing code whose behavior is not well defined by the language.
1 Like
#590
  1. A named object
  2. A variable is the name of a region in the memory.
  3. It’s the fact to reserve some memory in the RAM for the variable
  4. I-value has persistent address whereas r-value hasn’t
  5. It’s a variable which hasn’t any value, it’s behavior is undefined.
  6. Unpredictable behaviour resulting from the use of unitialised variables, C++ has no rules to determine what will happen.
1 Like
#591

1- Data structured in memory.
2- a named object.
3- It is the creation of a variable.
4- I values has assigned a place in memory. R values is a value without an address.
5-when we don’t assign a known value to that variable. Unexpected behavior.
6- Executing a code whose behavior is not well defined.

1 Like
#592
  1. What is a variable in C++? A named object is called a variable.
  2. What is Definition of a variable? It includes an object with an identifier (name), which stores data values of a specific type.
  3. What is Instantiation of a variable? Making a declaration statement called a definition - which creates an object and a memory address to store its value.
  4. What is the difference between an l-value and an r-value? An I-value points to a specific memory location and R-value points to a non specific location.
  5. What is an uninitialized variable and what kind of behaviour can you expect from such a variable? The variable has no value. Unexpected behaviour.
  6. What is undefined behaviour? A programs result when executed produce unexpected / random results.
1 Like
#593

  1. What is a variable in C++?
    In C++, we use variables to access memory. Variables have an identifier, a type, and a value

  2. What is the Definition of a variable?

A variable is a named region of memory.

  1. What is Instantiation of a variable?
    Instantiation means the object will be created and assigned a memory address by the compiler at runtime.

  2. What is the difference between an l-value and an r-value?
    An l-value is a variable that has a persistent address in memory. It is the value on the left hand side when an assignment is made.
    On the other hand, r-values are not associated with a persistent memory address. They are generally temporary in nature and are discarded at the end of the statement in which they occur.

  3. 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 not been given a value by the program (generally through initialization or assignment). Using the value stored in an uninitialized variable will result in undefined behavior.

  4. What is undefined behavior?
    Undefined behavior is the result of executing code whose behavior is not well defined by the language. The result can be almost anything, including something that behaves correctly.

1 Like
#594
  1. A variable in C++ is a named object.
  2. A kind of statement used to create a variable.
  3. Instantiation of a variable means that the object will be created and assigned a memory location.
  4. L-values have assigned memory addresses, r-values is basically anything that is not an l-value.
  5. An uninitialized variable is a variable that has not been given a known value. The behavior that can be expected from an uninitialized variable is unexpected/unpredictable.
  6. Undefined behavior is the result of executing code whose behavior is not well defined, with this undefined behavior, you don’t know what result you will get.
1 Like
#595

1. What is a variable in C++?
A variable is an object that has a name and an object is a piece of memory to store values.

2. What is the Definition of a variable?
To create a variable a special kind of declaration statement is required, which is called the definition of a variable.
For instance: int x; // Definition of x

3. What is the Instantiation of a variable?
When a variable is defined, a part of the memory from RAM is set aside.
For instance: int x; let variable x point to a memory location with address 1000.

4. What is the difference between an l-value and an r-value?
All the variables are L-value. An L-value is a value that has a persistent address in memory.

While R-values can be single numbers (like 5) or expressions (like 2+z). R-values refer to values that are not associated with a persistent memory address.

5. What is an uninitialized variable and what kind of behavior can you expect from such a variable?
A variable that has not been given a value either through initialization or assignment.
For instance: int x;
Uninitialized variables are very well capable of yielding undefined behavior.

6. What is undefined behavior?
Undefined behavior is a result of executing code whose behavior is not well defined by the language.
Example: use of uninitialized variables.

1 Like
#596
  1. A named region of storage
  2. you name the variable and specify the type of variable.
  3. a created object with an assigned memory address
  4. i-value has a designated address, an r-value points nowhere. They are more temporary that i-values
  5. a variable that has not been given a value and its behavior will be somewhat undefined
  6. the compiled program will not be doing anything meaningful, the behaviour of the programme will have no restrictions
1 Like
#597

  1. Objects can be named or unnamed (anonymous). A named object is called a variable. A named object is called a variable, and the name of the object is called an identifier.

  2. A single region of memory

  3. When a program is run (called runtime), the variable will be instantiated. Instantiation is a fancy word which means the object will be created, and assigned a memory address.

  4. An I-value refers to an object that persists beyond a single expression. An R-value is a temporary value that does not persist beyond the expression that it uses.

  5. An uninitialized variable is a variable that has not been given a value by the program.
    If you don’t initialize a variable, this variable will remain unidentified and takes on the value that was previously residing in that location of memory.

  6. Unpredictable behaviour occurs when a program does something unpredictable by a usual specified standard.

1 Like
#598
  1. What is a variable in C++?

A named object is called a variable

  1. What is the Definition of a variable?

An object is a region of storage (usually memory) that has a value and other associated properties

  1. What is Instantiation of a variable?

Instantiation means that an object is created and assigned to a memory address.

  1. What is the difference between an l-value and an r-value?

and l-value has a persistent address while an r-value does not.

  1. 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 not been given a value yet, in C++ when an uninitialized variable is created and put into memory it is automatically set as whatever was in that memory location already.

  1. What is undefined behavior?

Using the value from an uninitialized variable is an example of undefined behavior.

1 Like
#599

  1. Variables are the object that has a name where we put values in them.

  2. Variable is the data type like integers or float if you have decimals and char is you have single letter on it.

  3. Instantiation of a variable is a piece of memory set by the RAM.

  4. l - Value are objects that is located in the memory
    r -value are object that is not l-value
    example of this is i = 5 where i is the l-value and the 5 is the r-value.

  5. An uninitialized variable is a variable but the value isn’t there or you forgot to put the value example is int main {
    int x = 10;
    int y;
    int answer = x + y;

cout << answer << endl;
}
return 0;
as you can see the variable y has no value means the answer variable won’t work because y has no value on it.

  1. Undefined behavior can be something that is wrong with your code sometimes it’s also because of the uninitialized variable
1 Like
#600
  1. a variable is a named object,
  2. object is a region of storage mostly memory like RAM, inside the object are values, which are single pieces of data.
  3. Instantiation of a variable, is when a object is given a location in memory.
  4. l-value is a locator value that has an assigned location in memory, and the r-value is everything that is not a l-value.
  5. Uninitialized variable, is a variable that was declared inside a function but it was not assigned a value. an Uninitialized variable in an expression may give unexpected results or cause compilation of errors.
  6. Undefined behavior is using the value from an uninitialized variable, this will also cause you program not to work correctly.
1 Like
#601

1. What is a variable in C++?

A variable is a named object in C++, and an object is a region of storage (usually in memory) that holds a value and other properties.

2. What is the Definition of a variable?
Example: int x;
To define a variable, we must specify its type (int for integer type) and name (x).

3. What is Instantiation of a variable?
Instantiation, which happens at runtime, is creating an object and assigning a memory address to it. Before variables can be used to store values, they must first be instantiated.

4. What is the difference between an l-value and an r-value?
L - value - has a persistent address in memory and are usually the values on the left-hand side of an assignment. R-values are temporary, they don’t have a dedicated memory address. They are discarded after being evaluated.
ex) int a = 1 + b;
Here, a is the l-value and (1 + b) is the r-value

5. 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 defined but holds no value. For example, “int x;” would create an uninitialized variable x that holds no value at first.

When you try to use an uninitialized variable, you will get whatever value is present at its memory location, which could be any unpredictable number.

6. What is undefined behavior?
Undefined behaviour can arise from using uninitialized variables. Although the C++ compiler will execute the program, what exactly the program does will be unknown.

1 Like
#602
  1. A variable is an object (place in memory) that is given a name and can be used to store data.
  2. A declaration statement that sets out the parameters for that variable.
  3. Instantination is the creation of the variable and where it is assigned a region of memory.
  4. An lvalue always has a defined region in memory and can be used on the left side of a statement. Rvalues however, does not always have any storage associated with it.
  5. An uninitialized variable is one that has not been assigned a known value and can result in unexpected results.
  6. Undefined behaviour occurs when executing code that is not correctly defined in C++.
1 Like
#603
  1. A variable in C++ is a named object.
  2. Definition of variable is a special declaration statement used to create a variable. (ie. x or y).
  3. Instantiation of a variable is when a program is run an object is created and stored in a memory address.
  4. An lvalue defines a specific memory location, where as a rvalue does not define any location.
  5. An unutilized variable is a variable that has not been given a know location, causing you to get or not get the same results in your code.
  6. Undefined behavior is code that is not well defined in C++ code causing many potential issues to occur in your code.
1 Like
#604
  1. What is a variable in C++? declaration statement called a definition
  2. What is the Definition of a variable? a named object
  3. What is Instantiation of a variable?
  4. What is the difference between an l-value and an r-value? Ivalues have persistent addresses in memory r down not and are discarded at the end of the statement
  5. What is an uninitialized variable and what kind of behavior can you expect from such a variable? variables that have not been given a value
  6. What is undefined behavior? behavior whos code is not well defined
#605

  1. A named object is called a variable

  2. the name of the variable

3.Instantiation is a fancy word that means the object will be created and assigned a memory address

4.l-value has-persistent address & r-value is not associated with a persistent memory address.

  1. a variable that has no memory location. We can expect anything except what we expected the variable value to be.

  2. the resulting value of an uninitialized variable.

1 Like