What is the significance of the R-value in determining the effectiveness of rock wool insulation?

What is the difference between lvalue and rvalue?

A variable is a named storage that can hold any value and has 2 values associated with it namely rvalue and lvalue. 'rvalue' is its data value that is its content and "lvalue" is its location value, that is memory address.

What is lvalue?

A variable has two associated value with it rvalue and lvalue. 'lvalue' is its location value, that is memory address.

What is Lvalue in c?

An lvalue is an object that can be assigned a value, i.e. it can be on the left side of an equals sign, hence the term lvalue.If the compiler is complaining, you are probably trying to assign a new value to an rvalue, such as an array name or constant.

What is L value error in C?

When there is no addressable value in program, then compiler will give lvalue error. Lvalue or location value is an address that is stored into while rvalue is the "read" value, ie., value of a constant or the value stored at a location. In the assignment a = 31; we have the lvalue of a used on the left hand side and the integer contant value 31 assigned to this location. In the assignment b = a; we have the rvalue of a (31) used to assign to the lvalue of b . So depending on which side of an assignment, we use the variable a , we get two different behaviors

What are the newest striking issues on C plus plus computer programming?

The newest striking issues with regards C++ can always be found be looking at the latest standard and those to come. The current standard is C++11, while the next two are currently known as C++14 and C++17. By examining the changes from the previous version to the next version one can determine what is new. The predecessor to C++11 was C++03. The naming convention follows the tradition of using the year of publication. Thus C++03 was published in 2003. One of the main changes between C++03 and C++11 was the introduction of the move constructor. This is useful when assigning a temporary object (an rvalue) to another object (an lvalue). Typically, resources are deep copied from the rvalue to the lvalue, which is expensive in terms of memory consumption and performance. However, since the rvalue is temporary, there is no need to copy the resources -- they can simply be moved. For instance, a std::vector<T> object is really nothing more than a wrapper for a C-style dynamic array with size. The size member is a simple primitive (an unsigned integer) that can easily be copied directly without any cost. However, the internal array is more complex in that it is a void pointer to memory that was dynamically allocated. With copy construction, the entire array must be copied to new memory which is then assigned to the lvalue's internal pointer. But with move construction, the lvalue's pointer simply copies the value of the rvalue's pointer before setting the rvalue's pointer to NULL. In other words, the lvalue takes ownership of the existing memory. When the rvalue falls from scope (which it must do since it is temporary), the memory is safe because its internal pointer is NULL. To achieve this, C++11 introduced an rvalue reference. In C++03, rvalues were typically considered const T& types. But an rvalue reference is a non-const T& type, identified by T&&. This semantic permits class designers to include both a copy and move constructor, as well as copy and move assignment operator overloads. Other major changes included the introduction of the constexpr keyword, which allowed functions and object constructors to be used within constant expressions. There were also changes to the plain old data semantic (POD) such that a class, struct or union can only be considered a POD if it is trivial, standard-layout, and all its non-static data members and base classes are PODs. By separating the trivial and standard-layout concepts, it is now possible to lose one without compromising the other, and thus be able to produce more complex PODs that are still memcpy-able and therefore compatible with C.

When will lvalue error occur in c?

When there is no addressable value in program, then compiler will give lvalue error. Lvalue or location value is an address that is stored into while rvalue is the "read" value, ie., value of a constant or the value stored at a location. In the assignment a = 31; we have the lvalue of a used on the left hand side and the integer contant value 31 assigned to this location. In the assignment b = a; we have the rvalue of a (31) used to assign to the lvalue of b . So depending on which side of an assignment, we use the variable a , we get two different behaviors

Pointer is a variable holding a memory address?

pointer is a derived datatype which contains memory addresses as their values. program:- #include<stdio.h> #include<conio.h> void main() { int m=5,*p; clrscr(); p=&m; printf("address of variable m is %p",(void *)p); }

What is the difference between a constructor and its corresponding overloaded assignment operator?

The copy constructor is used to initialize a new instance from an old instance, and is called when passing variables by value into functions or as return values out of functions. The assignment operator is used to change an existing instance to have the same values as the rvalue, which means that the instance has to be destroyed and re-initialized if it has internal dynamic memory.

What is the r-value of 2 foam sound board?

I assume you mean 2 inch thick foam sound board??? The answer lies in what type of foam specifically you are speaking of.Polyisocyanurate foam has an rvalue of approx. r-7 per inch,being one of the higher r value foams readily available in 4'x8' sheet size.Polystyrene foam board,commonly found in building centers and home centers,and commonly referred to as "Dow" board has an r value of approx. r-5 per inch.To calculate the 2" thickness you reference,simply double the r value given(r value is generally stated as "r value per inch".Thus ,2" polystyrene has an r value of r-10 (r-5/inch x 2).These are fairly general guidelines,and depending on your application,you may want to find more detailed specifications that speak to degradation of R value over time,properties and characteristics of various foam types,etc,etc.

Estimate cost of wiring a new home?

Depending on the size of the new home, it will cost between 1,500 and 3,000 dollars to run electrical wiring. The switches, boxes, and other materials will cost more or less depending on the number needed. <<>> On the average estimating a new home is $200.00 an outlet and $15.00 an amp for the service installation. At these prices you will get a qualified journeyman licensed to take out permits and a contractor that will stand behind his work if something should go wrong. Remember to tender the job to at least three different contractors for pricing before committing to let the job. The first question to ask the contractor is do you need a permit. If the answer is no, move on to another contractor. Every job needs to be inspected by an electrical inspector, your safety is at stake. Also when dealing with insurance companies, if there is no permit of inspection then there is no claim paid out to the home owner should damage be done to the home because of the non inspected wiring.

What is the difference in boiling pure water on a mountain top and at sea level?

The boiling point of water at sea level is 100 degrees centigrade. but the boiling point of water at a mountain top will depend on the atmospheric pressure of the air around that mountain top area at the time . if u were to measure the air pressure as u climb a mountain u would notice a change ; a reduction in air pressure . hence as you approach the top of the mountain the air pressure would have been seen to reduce to a much lowe rvalue that that at sea level height . i think it can be as low as 70 degrees centigrade at some mountain tops. in comparison if u had an enclosed metal vessel and made the pressure inside that increase to a very high value, the water would now boil at a much greater temperature , 250 degrees ? maybe .

What are the factors that determine the choice of programming language when developing an application?

It's more often than not, not a programmers choice, but when it is, typically: Platform (e.g. if you are writing something for Android, or iOS, your choices are somewhat limited, same goes for cross OS compatibility) Objective (e.g. are you writing a kernel module or a website) Familiarity (e.g. if i know Ruby and don't know PHP) Performance needs (e.g. am i writing a network stack or a text editor) Libraries (e.g. PHP built-in database libraries, Java does not) Language specifics/purpose (e.g. it's a good idea to write a protocol in more functional programming language like Scala than in Perl or Java)