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What else can I help you with?
What are the different types of overloading allowed in c plus plus?
There are only two types: user-defined and compiler-generated. User-defined overloads are the ones you specifically write. Compiler-generated overloads are created by the compiler based upon a template function that you define. The only real difference is that with a template function you only need to write one version of the function, and the compiler will generate the actual overloads on an as-required basis. With user-defined overloads you must write each overload in full. Template functions save a lot of time and maintenance, however they are only practical when the only difference between the overloads is the type of argument. That is, if the implementation is exactly the same regardless of type, then template functions are clearly a better option than writing out each overload by hand. Moreover, if you ever need to alter the implementation, there's only one function to modify.
What do you mean by Instantiating the function template?
Function templates are generic functions for which at least one argument must be a generic type. You cannot instantiate a generic type without knowing its actual type, so until you provide an actual type for the function, the function template cannot be instantiated. You provide an actual type simply by calling the function. If an unambiguous template exists, the compiler generates the actual function for you. At that point the function is said to have been instantiated, just as if you'd written the function by hand. If you call the function again with different types, then new instances of the function are instantiated to match those types, just as if you'd manually written the overloads yourself.
Why we use function prototyping in c language?
You could just define the whole function before it is called, like this:void do_nothing(){}main(){do_nothing();}but if you define the function after it is called, the compiler will arrive at the function's calling before its actual definition. If you prototype your function earlier in the code than the function's call, the compiler will look for the function first.Hope I was able to help.
What is the advantage of using function prototypes in a program?
Function prototypes allow the compiler to emit machine code in a single pass. Consider the following: int main (void) { int x; x = foo (42); return 0; } In the above example, the compiler has not yet seen the prototype for the foo() function. Without a prototype the compiler cannot determine how much memory to allocate on the stack, nor can it determine if the function argument (42) or its return type should be converted to or from a type other than int. As such, the compiler cannot generate the required object code. Assuming the prototype appears later in the code, the compiler is forced to make two complete passes over the code before it can generate the object code. Had we specified the prototype for foo() before any use of the function, the compiler would have enough information to generate object code in a single pass: int foo (int); // prototype int main (void) { int x; x = foo (42); return 0; } Note that we don't need to define foo(). The implementation details may be contained in another translation unit entirely, but this does not matter. The offset addresses of all functions are simply symbolised and placed in the symbol table at the end of the object code. Once all translation units have been compiled to object code, the linker can use the tables to resolve symbolised offsets to their actual offsets.
What is the difference between inlinefunction and function overloading?
The normal way a function works is that whenever your code encounters a call to the function, it jumps to the body of the function code. An inline function tells the compiler that it should actually copy over the code from a function body into all places where that function is called. In some cases this can cause a dramatic reduction in run time, but in others it causes nothing more than increasing the size of the produced executable. Function overloading refers to the ability to have multiple functions with the same name, but different parameter types.
What are the generic facilities in c plus plus?
C++ facilitates generic programming through the use of templates. Template metaprogramming is the broader concept of templates because they allow the computation of code at compile time. In other words, the compiler writes the program for you, creating and manipulating classes and functions to suit your needs according to the templates that define them and the specific types, values and templates you provide as arguments. Thus we can think of templates as being generators (as in code generators). Generic programming usually begins with a concrete type which we then generalise through a template. This technique is known as "lifting". The concrete type may be a class or a function (including member functions). Once lifted, we can pass instances of that type to function templates that accept the template as an argument. A function template is often called an algorithm which is a procedure or formula for solving a problem using a series of finite computational steps to produce a result. An algorithm is generic insofar as the data it operates upon need not be of a specific type, provided the generic type has the specific characteristics or traits that are appropriate to the algorithm. Although template programming can result in a lot of code duplication, this is not the same as writing duplicate code by hand. Code duplication is a necessary evil, but compilers are much better at dealing with it than humans. When we duplicate code by hand, we increase the maintenance. Every time we alter the implementation we must make the same changes across all duplicates. This can easily lead to inconsistencies and program errors. By allowing the compiler to handle the duplication, we only have one implementation to worry about. As a trivial example, consider the concrete examples for the max function overload: int max (int a, int b) { return a<b?b:a; } double max (double a, double b) { return a<b?b:a; } While these function overloads are undoubtedly useful (returning the larger of two values), we can easily see that the implementation is exactly the same regardless of the type. Indeed, such a function is capable of handling any type that supports the less-than operator (<). Therefore rather than duplicating this code to cater for the myriad different types we could possibly pass to max (and including thousands upon thousands of headers that we may or may not need in any of our actual programs), it makes more sense for the compiler to generate the overloads for us, according to the types we actually pass to the function. In this way we not only cater for the types we actually use, we can also cater for types that do not yet exist! In this case, the only argument we need to parametrise is the typename because both the arguments and the return value are of the same type. Thus we'll denote the typename with the token T: T max (const T a, const T b) { return a<b?b:a; } As it stands, the compiler will now look for a declaration of type T and won't find one. However, T is not a type it is a typename token. Therefore we must inform the compiler of that fact: template<typename T> T max (T a, T b) { return a<b?b:a; } Now that the compiler is appeased, it is time to look at the implementation in more detail. The first thing to note is that the function does not modify either of its arguments, so it makes sense to declare them both const. template<typename T> T max (const T a, const T b) { return a<b?b:a; } While this is fine for primitive data types or any type that fits the word length of the underlying architecture, passing by value is not so efficient when it comes to passing larger and more complex objects. Therefore we should pass by reference to avoid the penalty of making unnecessary automatic copies: template<typename T> T max (const T& a, const T& b) { return a<b?b:a; } Finally, we note that we always return the value of either a or b. But since we passed them both by reference it makes sense to return by reference rather than to return a temporary value (incurring another unnecessary copy). In C++11 this is less of a problem because most classes now implement move semantics, however we cannot guarantee this is always the case, so let's err on the side of caution: template<typename T> T& max (const T& a, const T& b) { return a<b?b:a; } We could also return the value as a constant reference but in my experience this only serves to confuse. Let the caller decide whether the return should be const or not, our function is only concerned with which argument is the greater. At this point it is important to note that no code is actually generated by this function. When the compiler encounters a function template, it knows that it is merely a template and not an actual function. It will take note that the function template exists and cache its definition, however code can only be generated from a function template when we provide the function with an actual type, which we can only do by invoking the function: int x=42, y=69; // ... int a = max (x, y); Upon encountering this call, the compiler will generate the actual function for us: int& max (const int& a, const int& b) { return a<b?b:a; } However, even a half-decent compiler will recognise the golden opportunity for inline expansion and will eliminate the function call entirely: int x=42, y=69; // ... int a = x<y?y:x; The only caveat with templates is that the template must be completely visible to the compiler before it is used in code. Unlike ordinary types and functions, it is not enough that it merely be declared (as in a forward declaration), it must be fully defined as well. Thus you will often find template definitions in the same header as its declarations, and that same header included at the top of every source file that invokes the template. As mentioned near the top of this article, templates naturally incur code duplication which is a necessary evil but one that is tamed through templates. The compiler will only generate code for the types you actually use but with the massive scope of compile-time computation and inline expansion, your code will be leaner, meaner and much more easily maintained than if you did it all by hand. We've only scratched the surface of what is possible with templates. The best way to learn about generic programming is to make use of the generic types that already exist, particularly those in the standard template library (STL). You can learn a lot simply by examining the source code for these types.
What is the name of java compiler?
It is simply called the Java compiler. The actual program is usually called Javac.
What is a template class in c plus plus?
Templates allow us to reduce the need to write duplicate code ourselves and force the compiler to duplicate the code for us. This saves a great deal of time (and money) and greatly reduces code maintenance because there's only one version of the implementation to modify. This greatly reduces the chances of us making a mistake because the compiler will propagate all the changes for us. Moreover, we don't need to second-guess what data types we might need to cater for in the future because the compiler will generate specific versions on an as-required basis, according to the types we actually use -- including those we haven't yet designed!You've probably been taught that code duplication is a bad thing -- and you'd be right -- but it is also a necessary evil. The difference with templates is that rather than placing the onus upon the programmer to ensure the code duplication is consistent, the onus is placed entirely upon the compiler.So when do we need code duplication? We need it whenever the implementation of a function or a class differs only in the type of data they operate upon. That is, one class or function definition that caters for any data type, rather than creating many separate classes or functions for each data type. If the implementations are exactly the same in every way, then duplicate code is inevitable. It's simply a matter of whether we write it ourselves and accept all the pitfalls that come with that, or we let the compiler do all the donkey work for us. The latter is always the preferred option every time.Consider the following simple example:int max(int a, int b){ return(a
How can you create a language?
Writing a language converter is very much like writing a compiler. In fact, a compiler can be considered a language converter, when the target language is object code. The actual science of writing a compiler is complex.
How can you create a language converter?
Writing a language converter is very much like writing a compiler. In fact, a compiler can be considered a language converter, when the target language is object code. The actual science of writing a compiler is complex.
Why do you use standard template library in C plus plus?
Strictly speaking there is no need for function templates -- you could do it all by hand if you really wanted to. However, anything that aids in the reduction of duplicate source code is "a good thing" in my book. Code duplication increases code maintenance overheads, there's always the chance you'll forget to propagate changes consistently, and writing variations of a function that may or may not be used is simply a waste of time and effort.To understand the need for function templates it's best to look at how they actually work. Let's consider the following two function declarations:int GetMax(int a, int b){return(a>b?a:b);};float GetMax(float a, float b){return(a>b?a:b);};We can see that both functions have exactly the same body:{return(a>b?a:b);};These examples are fairly simple, but whether the function is complex or not, every time we need to pass a new data type to the GetMax() function we must declare a new definition of that function in order to handle that specific data type. Or we could write out every conceivable version of the GetMax() function in full, whether we intend to actually use it or not! That's certainly an option, but in a more complex function we may later decide to alter the implementation, in which case we must duplicate those changes across ever occurrence of the function. That's a lot of unnecessary work for just one function, and may introduce errors if we're not careful with our propagation of changes.Thankfully, the compiler can do all this work for us. We need only define the function once, and once only, and the compiler will generate all the necessary code based upon the type of data we actually pass the function. This ensures we don't create copies of the function we will never use, and greatly reduces the maintenance overhead should we ever need to alter the implementation of the function.We do this by using a function template.templateT GetMax(T a, T b){return(a>b?a:b);};Note that this is not a function, per se. It is a template for a function, whereby the variable T denotes a generic data type. Whenever we make a call to GetMax(), the compiler will automatically generate the necessary code for the actual function we need, replacing the generic data type T with the actual data type we pass into the function, such as int, or float.int a=1, b=2;int i=GetMax(i,j); // Generates the int variation of the function.float x=0.3, y=1.2;float f=GetMax(x,y); // Generates the float variation of the function.Now that we have a function template, we are no longer restricted to ints and floats any more. We can now use GetMax() with any data type we wish, without having to write specific functions for those types. The compiler does it all for us, automatically.DWORD p=0x000000FF, q=0x00000000;DWORD d=GetMax(p,q); // Generates a new variation of the function.
What are the benefits of templates in c plus plus?
Templates allow you to centralise code that only differs by type, but where the implementations are exactly the same. This reduces maintenance because all the code is one place and if modification is required, you only need to make the modification once, rather than once for each type which may lead to errors if you fail to propagate your changes. The compiler will generate the actual function overloads and class definitions for you, based upon the template and the types you actually use, rather than forcing you to write separate overloads and classes for types that might never be used.
