C++ Articles - Page 581 of 719

In C++ stream refers to the stream of characters that are transferred between the program thread and i/o.Stream classes in C++ are used to input and output operations on files and io devices. These classes have specific features and to handle input and output of the program.The iostream.h library holds all the stream classes in the C++ programming language.Let's see the hierarchy and learn about them, Now, let’s learn about the classes of the iostream library.ios class − This class is the base class for all stream classes. The streams can be input or output streams. This class defines members that ... Read More

A file is a memory location that stores word streams. In a file, there are various words. In this program, we will find all unique words from the file and print them.A unique word means the number of occurrences of the word is one in the file.For example, Tutorials point is best for programming tutorials.Here, the word tutorial occurs more than once, hence it is not unique. Rest all words are unique.AlgorithmTo check for unique words in the given file. Using iterator with two variables : data and occurence. Input : File Step 1 : Read each line from the ... Read More

Current day, date and time are all calendar dates that are printed on screen. In c++, the ctime library contains all the methods and variables related to date and time.You can also check current date and time details using the ctime library which contains methods to display time. The following methods are used to display details of date and time −time() − The time() method is used to find the current time. The return time of the time() method is time_t. time_t is the data type that can store time.localtime() − To convert the time_t type variables to a variable ... Read More

An iterator is an object just like a pointer that is used to iterate over elements of a container. The main advantage of using an iterator is to create a common interface and make the algorithm immune from the type of container used to implement it.In C++ standard library there are Types of iterators −Forward iteratorBidirectional iteratorInput iteratorOutput iteratorRandom Access iteratorThe program is to check which of the above iterators are used by the data structure.There are a few factors that can be useful for determining the type of iterator used.typeid, returns the type identification information at runtime.iterator traits, defines ... Read More

Date is number day, month and year. There are various ways to display a date.Here, we have a program to sort dates using selection sort. So let's learn about things that are used in this concept.Sorting datesThe concept of sorting dates needs a clear and well-versed knowledge of dates and their validations. Before we try sorting technique we need to check if the date inputted by the user is a valid date of not like 29-2 is only valid for leap years.After validation of dates comes the sorting of dates. For sorting, we will go in reverse order sorting years ... Read More

A subsequence is a sequence with the same order of the set of elements. For the sequence “stuv”, the subsequences are “stu”, “tuv”, “suv”, .... etc.For a string of length n, there can be 2n ways to create subsequence from the string.ExampleThe longest common subsequence for the strings “ ABCDGH ” and “ AEDFHR ” is of length 3. Live Demo#include #include using namespace std; int max(int a, int b); int lcs(char* X, char* Y, int m, int n){    if (m == 0 || n == 0)       return 0;    if (X[m - 1] == ... Read More

Hashing is the method by which we can map any length data element to a fixed size key. hashing works as key-value pairs.Hashing function is the function that does the mapping in a hash map. the data elements that are given as input to the Hash Function may get same hash key. In this case the elements may overlap. To avoid overlapping of elements which have the same hash key the concept of chaining was introduced.Creating a hashmapIn order to create a hashmap we need hashing function that will define the index value of the data element.We have a hash ... Read More

Mathematical calculations can be done in C++ programming language using the mathematical functions which are included in math or cmath library. These mathematical functions are defined to do complex mathematical calculations. Let’s learn each of them one by one −sineThe sin method is used to calculate the sin of the angle given as an argument in degrees. This function accepts one double integer as an argument and returns a double integer which is the value of sin(x°).double sin(double)Calling syntaxdouble x = sin(23.4);Example Live Demo#include #include using namespace std; int main(){    double x = 45.3;    cout

A map is a data structure that stores information in the form of key and value pairs. In C++, map is defined in STL (standard template library) and store keys in an ordered form.Syntax to define a map −map map_name;The data type of any of these two data of the map can be any of the data types. We can have any of the primary data types or derived data types as key or value data types in a map.We can use any of the data types as the data type of the key of the map. Even a user-defined ... Read More

What is a virtual function?A virtual function is a method that does not have a definition when defined in the base class. This method is left black in the parent class and it is redefined in the child class.What is an abstract class?An abstract class is a class that has abstract members or at least one pure virtual function in its definition. An abstract class can never be instanced (creating an object). It can only be inherited and the methods could be overwritten.Can there be any virtual Destructors?Yes, These are legal in C++, but these are destructors are for base ... Read More