This lesson and the next are optional reading for those desiring a deeper knowledge of C++ templates. Partial template specialization is not used all that often (but can be useful in specific cases). In lesson , you learned how expression parameters could be used to parameterize template classes. Let’s take …
In the previous lesson , we saw how it was possible to specialize functions in order to provide different functionality for specific data types. As it turns out, it is not only possible to specialize functions, it is also possible to specialize classes! Consider the case where you want a …
In previous lessons, you’ve learned how to use template type parameters to create functions and classes that are type independent. A template type parameter is a placeholder type that is substituted for a type passed in as an argument. However, template type parameters are not the only type of template …
In a previous chapter, we covered function templates (), which allow us to generalize functions to work with many different data types. While this is a great start down the road to generalized programming, it doesn’t solve all of our problems. Let’s take a look at an example of one …
In lesson , we discussed how the compiler will use function templates to instantiate functions, which are then compiled. We also noted that these functions may not compile, if the code in the function template tries to perform some operation that the actual type doesn’t support (such as adding integer …
Let’s say you wanted to write a function to calculate the maximum of two numbers. You might do so like this: int max(int x, int y) { return (x < y) ? y : x; // Note: we use < instead of > because std::max uses < } While the …
The file pointer Each file stream class contains a file pointer that is used to keep track of the current read/write position within the file. When something is read from or written to a file, the reading/writing happens at the file pointer’s current location. By default, when opening a file …
File I/O in C++ works very similarly to normal I/O (with a few minor added complexities). There are 3 basic file I/O classes in C++: ifstream (derived from istream), ofstream (derived from ostream), and fstream (derived from iostream). These classes do file input, output, and input/output respectively. To use the …
The ios_base class contains several state flags that are used to signal various conditions that may occur when using streams: Although these flags live in ios_base, because ios is derived from ios_base and ios takes less typing than ios_base, they are generally accessed through ios (e.g. as std::ios::failbit). ios also …
So far, all of the I/O examples you have seen have been writing to cout or reading from cin. However, there is another set of classes called the stream classes for strings that allow you to use the familiar insertions (<<) and extraction (>>) operators to work with strings. Like …
