#rvalues

[cerulity]

Actual additions to C for C++:

Namespaces

Visibility qualifiers

Member functions

Default arguments

Mental illnesses:

Copy constructors

Move constructors

lvalue and rvalue references

Rules of 0/3/5/6

<< and >> for ostreams and istreams

| for views and range

Templates

Concepts

Inheritance

Multiple inheritance

Virtual functions

= 0 for pure virtual

Dynamic casting

[souhaillaghchimdev]

C++ for Advanced Developers

C++ is a high-performance programming language known for its speed, flexibility, and depth. While beginners focus on syntax and basic constructs, advanced developers harness C++'s full potential by leveraging its powerful features like templates, memory management, and concurrency. In this post, we’ll explore the key areas that elevate your C++ skills to an expert level.

1. Mastering Templates and Meta-Programming

Templates are one of the most powerful features in C++. They allow you to write generic and reusable code. Advanced template usage includes:

Template Specialization

Variadic Templates (C++11 and beyond)

Template Metaprogramming using constexpr and if constexpr

template<typename T> void print(T value) { std::cout << value << std::endl; } // Variadic template example template<typename T, typename... Args> void printAll(T first, Args... args) { std::cout << first << " "; printAll(args...); }

2. Smart Pointers and RAII

Manual memory management is error-prone. Modern C++ introduces smart pointers such as:

std::unique_ptr: Exclusive ownership

std::shared_ptr: Shared ownership

std::weak_ptr: Non-owning references

RAII (Resource Acquisition Is Initialization) ensures that resources are released when objects go out of scope.#include <memory> void example() { std::unique_ptr<int> ptr = std::make_unique<int>(10); std::cout << *ptr << std::endl; }

3. Move Semantics and Rvalue References

To avoid unnecessary copying, modern C++ allows you to move resources using move semantics and rvalue references.

Use T&& to denote rvalue references

Implement move constructors and move assignment operators

class MyClass { std::vector<int> data; public: MyClass(std::vector<int>&& d) : data(std::move(d)) {} };

4. Concurrency and Multithreading

Modern C++ supports multithreading with the `<thread>` library. Key features include:

std::thread for spawning threads

std::mutex and std::lock_guard for synchronization

std::async and std::future for asynchronous tasks

#include <thread> void task() { std::cout << "Running in a thread" << std::endl; } int main() { std::thread t(task); t.join(); }

5. Lambda Expressions and Functional Programming

Lambdas make your code more concise and functional. You can capture variables by value or reference, and pass lambdas to algorithms.std::vector<int> nums = {1, 2, 3, 4}; std::for_each(nums.begin(), nums.end(), [](int x) { std::cout << x * x << " "; });

6. STL Mastery

The Standard Template Library (STL) provides containers and algorithms. Advanced usage includes:

Custom comparators with std::set or std::priority_queue

Using std::map, std::unordered_map, std::deque, etc.

Range-based algorithms (C++20: ranges::)

7. Best Practices for Large Codebases

Use header files responsibly to avoid multiple inclusions.

Follow the Rule of Five (or Zero) when implementing constructors and destructors.

Enable warnings and use static analysis tools.

Write unit tests and benchmarks to maintain code quality and performance.

Conclusion

Advanced C++ programming unlocks powerful capabilities for performance-critical applications. By mastering templates, smart pointers, multithreading, move semantics, and STL, you can write cleaner, faster, and more maintainable code. Keep experimenting with modern features from C++11 to C++20 and beyond — and never stop exploring!

[delmondo]

i used to kind of understand when people said "in c++ you only pay for what you use" (whether that'd be its numerous language features or abstractions) but i quickly realized sometime in the last 5 years that if someone's mostly useful library written in the language makes use of the fucking rule of 3/rule of 5 and/or RAII shit and, you sometimes have no choice but to either Cooperate with it, fully considering all the shit that could go wrong like "what behavior with this _actually_ trigger if if pass in an ordinary lvalue/prvalue/xvalue (reference)" into it".

constructors being the thing they decided to use to standardize "copying", "moving", and "initializing" things with a mostly uniform API is also extremely unhelpful because a constructor can theoretically do almost anything. it doesn't even have to "return" an initialized instance of something to you. in fact, it doesn't return anything. it's like a function, but it's not. but it is. it's like it can't decide how specific or nonspecific it wants to be. and there has to be at least 3 or 5 of them that you have to write EVERY time if you want anything even slightly nontrivial in them, and at that point you then must consider instances of this fucking thing "nontrivially copyable" so you may want to change the declaration of every function that accepts such a type of object as its arguments to accept an lvalue reference instead... and probably also write a separate version that accepts an rvalue reference. because passing in plain pointers is bad. because pointers are unstable. but so are references sometimes. so like.

so they wanted to make uniform the process of copying, moving, and initializing under a similar-looking syntactical pattern, but keeping these as gentle suggestions instead of rigidly-enforced linguistic constructs. ok, that's a non-negligible amount of work to implement in a compiler, but it can't be any more herculean than what it must be like to just simply maintain one for the language these days.

i am fighting fucking ghosts from over 40 years ago. join the club i guess

[data-science-and-ai]

Tarea 2 - Frecuencias y Regresión

Frecuencia de promedios 6 - 360 7 - 4079 8 - 8122 9 - 5035 10 - 39

Frecuencia de tipo de bachillerato de origen 0 - 14045 1 - 3590

Resultados de la regresión lineal

Pendiente de la línea de regresión 0.004224384216669276

Intersección de la línea de regresión 8.016945532217871

Coeficiente de correlación de Pearson. El cuadrado de rvalue es igual al coeficiente de determinación 0.002183244760831845

Valor p para una prueba de hipótesis cuya hipótesis nula es que la pendiente es cero, utilizando la prueba de Wald con distribución t del estadístico de prueba. 0.7718867792018003

Error estándar de la pendiente estimada, bajo el supuesto de normalidad residual. 0.014571251221020527

Conclusiónes:

- La Pendiente de regresión es positiva pero casi 0

- La relación entre las variables es muy débil y no significativa estadísticamente.

- El modelo de regresión lineal no es adecuado para explicar la variabilidad en la variable dependiente.

[u-train]

look you say that as a meme but...

templates are turning complete (lol)

templates are actually fill-in-the blank code. so, you cannot just have a typical .hpp and .cpp structure. because you know, the .hpp would only define the interface (control panel) but not the implementation (guts). you have to manually instantiate the implementation for the template otherwise linking errors. can you tell that I got bit by this and I'm bitter???

sfinae (if the first template didn't work try a different one. this is like having half-, one-, two-, and three-gallon containers. you have three gallons to store. you literally try filling each of them until you get the last container. lol!)

anonymous namespace

inline namespace?!

const-ing the this parameter of a method is just weird syntax to me.

forwarding references? wtf is this shit?

coroutines, what does this mean in cpp and why does cpp have this?

concepts (I just don't know, I think they're type classes but funky)

the most vexing parse (skill issue)

vector>> (X_X)

you can use macros to change true to false. or.. any keyword. lol.

operator overloading to make things that shouldn't be. ostream pipe for example...

static

varargs are silly imo

pointer-to-member operators. JUST LEARNED THIS!

rule of five (so silly)

PIMPL (okay buddy)

basic datatype are relatively sized and only specify minimal sizes.

at least we have cstdint (and some others?)

rvalues/lvalues, which aren't really right/left values.

move semantics, I think it makes sense, just not immediately intuitive.

and im so sure, this is just start. cpp have so many features that work together to make insane things possible!

that cat has every right to be like that. this meme is real.

[arahovsepyan]

View this post on Instagram

A post shared by Ara Hovsepyan, Architect (@arahovsepyan)

spit some bars about R-Values and U-Values... hit the link for the full vid! _________________________________ #rvalues #uvalues #architecture #architect #mnemonicdevice #architectrapper #architecturerap #thearchitectsmixtape #superarchitects #archinect #architectregistrationexam #ncarb #notly #ppd #pdd #buildingscience #buildingsciencefightclub #buildingscience101 #buildingsystems #energycalcs #title24 https://www.instagram.com/p/CCYsR1tpX79/?igshid=194ytoh2fjfvq

[jimsjoo]

error: lvalue required as increment

error: lvalue required as increment

What will be the value of x in the following C++ program? #include<iostream> using namespace std; int main(){ int aaa=1; int xxx=(aaa++)++; cout<< xxx <<endl; return 0; } The variable 'aaa' has 1 at first. When declared as an integer variable, xxx seems to have 3 because we are likely to assume that (aaa++) increases 'aaa' by 1 to make it 2 and '++' after (aaa++) makes the result of (aaa++)…

[sidnazpro2020]

Latest News Today - India Coronavirus Cases: India's 'R-Value' Inching Up,

Latest News Today – India Coronavirus Cases: India’s ‘R-Value’ Inching Up,

India has logged over 3.16 crore cases since the start of the pandemic. New Delhi: India’s ‘R-Value’ is inching up, and it’s a cause of concern, AIIMS Chief Dr Randeep Guleria told NDTV on Saturday, stressing on the need of aggressive containment strategies in the parts of the country that are witnessing a surge in fresh Covid infections. His remarks come amid concern over a third…

[data-science-and-ai]

Tarea 2 - Código Python

Instala la librería

Se necesita restaurar el kernel

%pip install scikit-learn

import numpy as np import pandas as pd import seaborn as sns from scipy import stats

df = pd.read_csv('/Users/alejandroflores/Desktop/Curso_Regresion_Coursera/Tarea_2.csv')

Cambia el tipo de dato y redondea el promedio

df['promedio'] = df['promedio'].fillna(0).astype(int)

Se recodifican los valores del tipo de bachillerato

df.loc[df.tipo_bach ==1, 'tipo_bach'] = 0 df.loc[df.tipo_bach ==2, 'tipo_bach'] = 1

sns.jointplot(x="tipo_bach", y="promedio", data=df, alpha=0.5)

x .- variable independiente / predictiva

y .- Variable resultado / dependiente

alpha .- ilumina los puntos de acuerdo a la densidad

-

sns.pairplot(df, kind='scatter', plot_kws={'alpha': 0.4})

Graficación de la regresión lineal

sns.lmplot(x="tipo_bach", y="promedio", data=df, scatter_kws={'alpha':0.3})

Frecuencia de promedios

lista_promedio = df['promedio'].values.tolist() frecuencia_promedio = pd.Series(lista_promedio).value_counts() print ("\nFrecuencia de promedios\n" ,frecuencia_promedio.sort_index(ascending=True))

Frecuencia de tipos de bachillerato

lista_tipo_bach = df['tipo_bach'].values.tolist() frecuencia_tipo_bach = pd.Series(lista_tipo_bach).value_counts() print ("\nFrecuencia de tipo de bachillerato de origen\n" ,frecuencia_tipo_bach.sort_index(ascending=True))

+

Calcula la regresión lineal.

slope, intercept, r_value, p_value, std_err = stats.linregress(df.tipo_bach,df.promedio) print ("\nPendiente de la línea de regresión\n" ,slope) print ("\nIntersección de la línea de regresión\n" ,intercept) print ("\nCoeficiente de correlación de Pearson. El cuadrado de rvalue es igual al coeficiente de determinación\n" ,r_value) print ("\nValor p para una prueba de hipótesis cuya hipótesis nula es que la pendiente es cero, utilizando la prueba de Wald con distribución t del estadístico de prueba.\n" ,p_value) print ("\nError estándar de la pendiente estimada, bajo el supuesto de normalidad residual.\n" ,std_err)

[zebrablinds-ca]

New Post has been published on https://www.zebrablinds.ca/blog/how-to-get-the-best-r-value-for-your-windows-10-2020-44/

How to Get the Best R-Value for Your Windows

[stellrrinsulation]

The truth about fixing your crawlspace insulation! https://t.co/5J5XA9y7Mi #insulation #sprayfoam #insulationremoval #crawlspaceinsulation #wallinsulation #stellrr #sprayfoaminsulation #Austin #rvalue #dehumidifier #insulationcontractor #remodeling

The truth about fixing your crawlspace insulation! https://t.co/5J5XA9y7Mi #insulation #sprayfoam #insulationremoval #crawlspaceinsulation #wallinsulation #stellrr #sprayfoaminsulation #Austin #rvalue #dehumidifier #insulationcontractor #remodeling

— Stellrr Insulation (@stellrrinsulate) Mar 1, 2023

from Twitter https://twitter.com/stellrrinsulate

[jtleepp]

lvalues and rvalues

The topic that inspired me to create this page, lvalues and rvalues. These rs and ls stand for left and right, referring to the side of in an assignment that value would be expected to occur.

A lvalue is a variable. You would expect this to live in the heap or stack, and it's address should be viewable with the reference of unary operator (&).

On the other hand (side of the expression), a rvalue is easiest to think of as a literal. They do not have a memory address that can be stored. Literals are the example of this I gave, but return values of functions also fit this category. So I guess that means they live in the stack or text? Seems odd to me.

Anyway, the real question is why are these useful. And it's because you can overload functions to handle these cases separately. probably other reasons as well. If you are writing a sorting function that doesn't want to modify the array passed to it, but you could increase efficiency if you did, you know with a rvalue you can modify the array in-place. Neat.

Now the function that sent me down this rabbit hole, std::move. Gotta go figure out what it does.

[sidnazpro2020]

Latest News Today - India Reports Most New Covid Cases In 3 Weeks As R-Value

Latest News Today – India Reports Most New Covid Cases In 3 Weeks As R-Value

More than 45.55 crore vaccine doses have been administered in the country so far. New Delhi: India’s Covid graph continued to show an upward trend as the country reported 44,230 new cases on Friday, the most in three weeks, amid fears of another wave of infections. The spread of the disease – which had eased off after a peak of four lakh daily cases in May – has forced at least one state to lock…

[jr3hp-blog]

Some in progress and completion shots of an attic air sealing and insulation repair job. What was thought to be R30 was performing at about an R5. This is in a young subdivision behind the #airnationalguard base near #schenectady Probably by a reputable developer..This home is only 17 years old but had several problems in the attic. I bet every other house in the subdivision could use the same repairs. Image 1: See the stink bug. We saw many of them near the air leakage points that are now sealed up. Guess how these pests can get into your home? Well not those buggers are not getting in this home anymore. Image 2: Insulation not in contact with the ceiling surface below it. Basically zero #rvalue if it’s not actually in contact with the air barrier(drywall ceiling). We placed it back down in contact and filled in the gaps with loose fill #blowninsulation Image 3: Attic knee-wall showing netting being placed up that will actually keep the vertical insulation in contact with the sheetrock. We packed some cellulose under the netting for a little extra r value and pack/push the insulation in contact with the sheetrock. Image 4 and 5: The finished product with just a dusting if cellulose. In this case it was 225 lbs of insulation. Mostly to just fill in gaps and get the R30 to actually perform as it should. Image 6: Cross sectional view of the attic hatch. There’s a layer of 1” and 2” foamboard for a total of R18. The trick to actually getting the R18 is the caulk seen in-between the layers. Small details critical for real results. #homeperformance #empowerny (at Glenville, New York) https://www.instagram.com/p/BwI9SL5Dvi0/?utm_source=ig_tumblr_share&igshid=11r9j7brgyks3

[arunabadami-blog]

Top 25 C++ Interview Questions for Experienced

Q #1) What is the basic structure of a C++ program?

In cases like this, we're using a directive that informs the compiler to add a header while"iostream.h" that is utilized for fundamental input/output later from the program.

The following line is your"primary" function that returns an integer. The major function is the beginning point of implementation for any C++ program. Irrespective of its status in the source code file, the principal function's contents are always implemented first from the C++ compiler.

We could observe open curly braces that point to the beginning of a block of code within another line. Next, we view the programming education or the amount of code that utilizes the count that's the standard output stream (its definition is current in iostream.h).

This output takes a series of characters and prints into a regular output device. . Please be aware that every C++ schooling ends with a semicolon (;-RRB-, which will be very much needed, and omitting it's going to lead to compilation errors.

Before shutting the braces}we visit the following line" return." This is the come the point to the major function.

Each C++ application will have a fundamental arrangement, as shown above, having a preprocessor directive, chief purpose announcement followed by a block of code, and a returning point to the major purpose, which indicates successful implementation of this program.

Q #2) Which are the Opinions in C++?

Answer: Remarks in C++ are merely a bit of source code dismissed by the compiler. They are only beneficial to get a developer to add a description or additional information regarding their origin code.

Q #3) Difference within Declaration and Definition of a variable.

Response: The statement of a factor is simply defining the data type of a variable and the variable name. As a consequence of the announcement, we inform the compiler to book the area for a memory factor based on the data type defined.

Q #4) Comment on Local and Global extent of a variable.

Answer: The range of a variable is defined as the degree of the app code where the factor remains active, i.e., it could be announced, defined, or worked with.

There are two Kinds of extent in C++:

Neighborhood Scope: A factor is said to have a local range or is local when it's declared in a code block. The factor remains active only within the cube and isn't available outside the code block.

International Scope: A factor has a global range when it's available throughout the application. A global variable is declared in addition to the app before all of the function definitions.

Q #5) What's the precedence when there are a worldwide variable and a neighborhood factor from the app with the same title?

Answer: Whenever there's a local variable with the same title as a global variable, the compiler gives precedence to the local factor.

Q #6) If there are a worldwide variable and Local factor with the same title, how will you get the global variable?

Answer: whenever there are two factors with the identical title but a different extent, i.e., one is a local variable, and the other is a global variable, the compiler will give decision to a local factor.

Applying this operator, we could get the value of this global factor.

Q #7) How many methods are there to initialize an int with a Constant?

Answer: There are just two ways:

The initial format employs conventional C notation.

Q #8) What's a Constant?

Answer A constant is an expression which has a fixed value.

Aside from the decimal, C++ additionally supports two constants, i.e., octal (into the base 8) and hexadecimal (into the bottom 16) constants.

Q #9) How do you define/declare constants in C++?

Answer: In C++we could specify our constants with the #define preprocessor directive.

Q #10) Comment on Assignment Operator in C++.

Answer: Assignment operator at C++ is employed to assign a value to some other variable.

A = 5;

The line of code specifies the integer value 5 to changeable a.

The part in the operator's left is called an lvalue (left value) along with the best as rvalue (good value). Lworth should stay a factor, whereas the ideal side may be a constant, a variable, the result of an operation, or some other mixture of those.

The mission operation always occurs in the right to left rather than in reverse.

One property that C++ has within the other programming languages is the assignment operator may be utilized as the value (or a part of an rvalue) for a different mission.

Q #11) What's the distinction between equivalent to -LRB-==-RRB- and Assignment Operator (=-RRB-?

Answer: In C++, equivalent to -LRB-==-RRB- and assignment operator (=-RRB- are just two entirely different operators.

Equal into -LRB-==-RRB- is a relational equality operator which evaluates two expressions to determine whether they're equivalent and returns true if they're similar and false if they're not.

The assignment operator (=-RRB- can be employed to assign a value to some variable. Hence, we may have an intricate assignment performance within the relational equality operator for analysis.

Q #12) What are the different Arithmetic Operators in C++?

Answer: C++ supports the following arithmetic operators:

+ addition

– subtraction

* multiplication

/ division

% module

Q #13) Which are a Variety of Compound Assignment Operators in C++?

Answer: Following will be the Compound assignation operators at C++:

Q #14) State the difference between Pre and Post Increment/Decrement Operations.

Answer: C++ enables two operators, i.e ++ (increment) and --(decrement), which permit you to add 1 to the present value of a factor and subtract one from the factor, respectively.

Q #15) Which will be the Extraction and Insertion operators at C++? Explain with illustrations.

Answer: From the iostream.h library of C++, cin, and cout would be the 2 data streams which are used for output and input respectively. Cout is generally directed to the display and cin is delegated to the computer keyboard.

"cin" (extraction operator): By utilizing overloaded operator >> using cin flow, C++ manages the standard input.

As shown from the preceding case, an integer variable'age' is announced and it waits for cin (keyboard) to input the information. "cin" procedures the input when the RETURN key is pressed.

It transmits the information that followed it to the cout stream.

Explain with illustrations.

Q #16) What is the difference between while and do while loop? Explain with examples.

Answer: The arrangement of while loop in C++ is:

The announcement block below while is implemented so long as the illness in the given expression is true.

Q #17) What do you mean by ‘void’ return type?

Answer: All works must return a value according to the overall syntax.

Nonetheless, in the event, if we do not need a function to return some value, we utilize"emptiness " to imply that. It follows that we utilize"emptiness " to signify that the function has no return value or it yields"emptiness ".

Q #18) Explain Pass by Value and Pass by Reference.

Answer: whilst passing parameters into the function utilizing"Pass by Value", we pass a copy of the parameters into the function.

Therefore, whatever alterations are made to the parameters in the called function aren't handed back to the calling function. Thus the variables from the calling function stay unchanged.

Q #19) Which are Default Parameters? How are they assessed at the C++ work?

Answer: Default Parameter is a value that's assigned to each parameter whilst announcing a purpose.

This value can be used if this parameter is left clean when calling to the purpose. To define a default value for a specific parameter, we just assign a value to the parameter from the function statement.

If the value isn't passed for this parameter through the function call, then the compiler uses the default value supplied. When a value is defined, then that default value is stepped on along with the passed value is utilized.

Q #20) What's an Inline role in C++?

Answer: Inline function is a function that's compiled by the compiler since the purpose of calling the function, and the code has been substituted at that point. This makes compiling quicker. This function is characterized by prefixing the function prototype using the keyword"inline."

Such acts are valuable only when the code of this inline function is small and easy. Though a purpose is described as Inline, it's completely compiler determined to appraise it as directional or not.

Advanced-Data Construction

Arrays

Q #21) Why are arrays generally processed together for loop?

Answer: Array employs the index to traverse all its components.

If A is an array, then all its components are obtained as A[I]. Everything is necessary for this to work is an iterative block using a loop variable I, which functions as an indicator (counter) incrementing from 0 to A.length-1.

This is just what a loop does, and that is why we process arrays using for loops.

"delete" is used to discharge one chunk of memory that was allocated with new.

Q #23) What's wrong with this code?

Answer: the aforementioned code will be syntactically correct and will compile fine.

The one issue is it will only delete the first part of this array. Although the whole selection is deleted, just the destructor of this first element will be called, and the memory to the first element is published.

Q #24) What is the sequence in which the items in an array are destroyed?

Answer: Objects within an array are destructed in the opposite order of construction: First assembled, last destructed.

Q #25) What's wrong with this code?

Answer: From the preceding code, the pointer is null. Per the C++ 03 typical, it is perfectly legal to call delete on a NULL pointer. The delete operator will look after the NULL test internally.

know more

[zebrablinds-ca]

New Post has been published on https://www.zebrablinds.ca/blog/what-is-best-r-value-for-windows-01-2020-05/

What Is the Best R Value for Windows?