User-Defined Literals in C++

Arnab Chakraborty
Updated on 27-Aug-2020 14:00:41

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Here we will see the concept of the user-defined literals in C++. From C++ version 11, the User Defined Literals (UDL) are added in C++. C++ also provides literals for a variety of built-in types but these are limited.Built-in Literals −31 (Integer)3.5 (Double)4.2F (Float)'p' (Character)31ULL (Unsigned Long Long)0xD0 (Unsigned Hexadecimal Integer)"pq" (String)Apart from the built-in literals, sometimes we need user defined literals. There are few reasons behind that. Let us see with few examples −Suppose we want to define one weight variable, but we cannot specify the units, like if we define as follows −long double Weight = 3.5;We have ... Read More

Uninitialized Primitive Data Types in C/C++

Nishtha Thakur
Updated on 27-Aug-2020 13:56:42

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One of the most frequent question is what will be the value of some uninitialized primitive data values in C or C++? Well the answer will be different in different systems. We can assume the compiler will assign 0 into the variables. It can be done for integer as 0, for float 0.0, but what will be for character type data?Example#include using namespace std; main() {    char a;    float b;    int c;    double d;    long e;    cout

Uniform Initialization in C++

Arnab Chakraborty
Updated on 27-Aug-2020 13:55:32

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Here we will discuss about the uniform initialization in C++. This is supported from C++11 version. The uniform initialization is a feature that permits the usage of a consistent syntax to initialize variables and objects which are ranging from primitive type to aggregates. In other words, it introduces brace-initialization that applies braces ({}) to enclose initializer values.Syntaxtype var_name{argument_1, argument_2, .... argument_n}Initialize Dynamically allocated arraysExample (C++)Let us see the following implementation to get better understanding − Live Demo#include using namespace std; int main() {    int* pointer = new int[5]{ 10, 20, 30, 40, 50 };    cout

Fill 8 Numbers in Grid with Given Conditions in C++

Arnab Chakraborty
Updated on 27-Aug-2020 13:53:49

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Suppose we want to place 1, 2, 3, 4, 5, 6, 7, 8, into the eight circles in the given figure, in this way that no number is adjacent to a number that is next to it in the sequence.So, if the input is like0-1-10-1-1-1-10-1-10then the output will beTo solve this, we will follow these steps −N := 3, M := 4NOTCONSIDERED := -1Define a function present_in_grid(), this will take grid[N][M], num, for initialize i := 0, when i < N, update (increase i by 1), do:for initialize j := 0, when j < M, update (increase j by 1), ... Read More

Traversing a Map or Unordered Map in C++ STL

Arnab Chakraborty
Updated on 27-Aug-2020 13:51:33

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Here we will see the map container and its use in C++. The maps are defined as associative containers that store elements in a hash-mapped fashion. Each element is associated with a key and value. No two mapped values can have identical keys. These are some fundamental methods that are present inside the map container in C++.begin(): This returns an iterator to the first element in the map.end()− This returns an iterator to the theoretical element that follows last element in the map.size() − This returns the number of elements in the map.max_size() − This returns the maximum number of ... Read More

Heap in C++ STL: Make Heap, Push Heap, Pop Heap, Sort Heap

Arnab Chakraborty
Updated on 27-Aug-2020 13:49:11

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In this section we will see the heap data structure present in C++ STL. This permits faster input into heap and retrieval of a number always results in the largest number i.e. largest number of the remaining numbers is popped out each time. Other elements of the heap are arranged which depends on the implementation. The heap operations are as follows −make_heap() − This converts a range in a container to a heap.front() − This returns first element of heap which is the largest number.ExampleLet us see the following implementation to get better understanding − Live Demo#include using namespace std; int ... Read More

Geometry Using Complex Numbers in C++

Arnab Chakraborty
Updated on 27-Aug-2020 13:46:10

336 Views

In this section, we will see how to make point class using complex class from STL in C++. And apply them on some geometry related problems. The complex number is present inside the complex class from STL (#include )Defining Point ClassTo make complex to point, we will change the name of the complex as point, then change x to real() of complex class and y to imag() of complex class. Thus, we can simulate the point class.# include typedef complex point; # define x real() # define y imag()We have to keep in mind that the x and y ... Read More

Generate Test Cases in C++

Arnab Chakraborty
Updated on 27-Aug-2020 13:43:39

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In this section we will see how we can use C++ STL function to generate test cases. Sometimes generating test cases for array programs can be very complicated and inefficient process. C++ provides two methods to generate test cases. These methods are as follows −The generate() methodThe C++ function std::algorithm::generate() assigns the value returned by successive calls to gen to the elements in the range of first to last. It takes three parameters first, last and gen, these are forward iterator to the initial position, backward iterator to the final position and generator function that is called with no argument, ... Read More

Check If a Number is Primorial Prime in Python

Arnab Chakraborty
Updated on 27-Aug-2020 13:41:55

836 Views

Suppose we have a number n, we have to check whether n is a primorial prime or not. A number is said to be a primorial prime when it is a prime number of the form pN# + 1 or pN# – 1 , where pN# indicates the primorial of pN such that the product of first N prime numbers.So, if the input is like 29, then the output will be True as 29 is Primorial prime of the form pN - 1 if N=3, Primorial is 2*3*5 = 30 and 30-1 = 29.To solve this, we will follow these ... Read More

Gaussian Filter Generation in C++

Arnab Chakraborty
Updated on 27-Aug-2020 13:41:20

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As we know the Gaussian Filtering is very much useful applied in the field of image processing. It is used to reduce the noise of an image. In this section we will see how to generate a 2D Gaussian Kernel. Gaussian Distribution for generating 2D kernel is as follows.$$G(x,y)= \frac{1}{2\Pi\:\sigma^{2}}e^{\frac{x^{2}+y^{2}}{2\sigma^{2}}}$$ExampleLet us see the following implementation to get better understanding − Live Demo#include #include #include #define PI 3.1415 using namespace std; void calc_filter(double kernel[][5]) {    double sigma = 1.0;    double p, q = 2.0 * sigma * sigma;    double sum = 0.0;    for (int x = -2; x

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