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Page 1470 of 2109
Removing an element from C++ std::vector<> by index?
Remove an element from C++ std::vector by index can be done by following way −Example#include #include using namespace std; int main() { vector v; //declare vector //insert elements into vector v.push_back(-10); v.push_back(7); v.push_back(6); // Deletes the first element (v[0]) v.erase(v.begin() ); for (int i = 0; i < v.size(); i++) cout
Read MoreRAII and smart pointers in C++
RAII in C++RAII (Resource Acquisition Is Initialization) is C++ technique which control the life cycle of resource. It is a class variant and is tied to object life time.It encapsulates several resources into class where resource allocation is done by constructor during object creation and resource deallocation is done by destructor during object destruction.Resource is guaranteed to be held till the object is alive.Examplevoid file_write { Static mutex m; //mutex to protect file access lock_guard lock(m); //lock mutex before accessing file ofstream file("a.txt"); if (!file.is_open()) //if file is not open throw runtime_error("unable to open file"); ...
Read MoreWhy do we pass a Pointer by Reference in C++?
If we need to modify a pointer rather than the object that the pointer is pointing to, we pass a pointer by reference.Here is an example of how to pass a pointer by reference −Example#include using namespace std; void Decrement( int*& d ) { --d; } int main( void ) { int a = 26; int* ptr = &a; // pointer to pass // print before decrement cout
Read MoreSorting in C++
In this section we will see how to perform sorting algorithm in C++. A sorted array is an array in which each of the elements are sorted in some order such as numerical, alphabetical etc. There are many algorithms to sort a numerical array such as bubble sort, insertion sort, selection sort, merge sort, quick sort, heap sort etc. More details about sorting the array using selection sort are given below.The selection sort is a sorting method that yields a sorted array. It does so by repeatedly finding the smallest element in the array and interchanging it with the element ...
Read MoreC++ Program to Check Whether an Input Binary Tree is the Sub Tree of the Binary Tree
A binary tree is a tree data structure in which each node has at most two children, which are defined as left child and right child.AlgorithmBegin function identical(): Take two nodes r1 and r2 as parameter. If r1 and r2 is NULL then Return true. If r1 or r2 is NULL then Return false. Return (r1->d is equal to r2->d and Call function Identical(r1->l, r2->l) and Call functions Identical(r1->r, r2->r) ); ...
Read MoreC++ Program to Construct an Expression Tree for a Postfix Expression
An expression tree is basically a binary tree which is used to represent expressions. In expression tree, nodes correspond to the operator and each leaf node corresponds to the operand. This is a C++ program to construct an expression tree for a postfix Expression in inorder, preorder and postorder traversals.AlgorithmBegin Function r() has a character variable as parameter. If the characters are + or - or * or / then Return will be -1 If the characters are from A to Z then Return will ...
Read MoreComplex numbers in C++
In this section we will see how to create and use complex numbers in C++. We can create complex number class in C++, that can hold the real and imaginary part of the complex number as member elements. There will be some member functions that are used to handle this class.In this example we are creating one complex type class, a function to display the complex number into correct format. Two additional methods to add and subtract two complex numbers etc.Example#include using namespace std; class complex { int real, img; public: complex() { ...
Read MoreC++ Program to use above below primitive to test whether two lines intersect
Here is a C++ program to use above below primitive to test whether two lines intersect. It can be used to test whether a line intersects a line segment. It does if and only if one endpoint of the segment is to the left of the line and the other is to the right.AlgorithmBegin For generating equation of the first line, generate random numbers for coefficient of x and y by using rand at every time of compilation. For generating equation of the second line, generate random numbers for coefficient of x and y by using rand at ...
Read MoreC++ Program to Implement Johnson's Algorithm
Here we will see the Johnson’s Algorithm to find shortest path between two vertices. The graph is given here. The shortest path between the edges is like below. This program will take the number of vertices, number of edges, and the edges with their costs.Input − Vertices: 3Edges: 5Edge with costs −1 2 82 1 121 3 223 1 62 3 4Output − The distance matrix of the graph.081210046140AlgorithmjohnsonAlgorithm(cost)Input − The cost matrix of given Graph.Output − Matrix to for shortest path between any vertex to any vertex.Begin Create another matrix ‘A’ same as cost matrix, if there is no ...
Read MoreComparison of Exception Handling in C++ and Java
The exception handling feature is present almost any object oriented languages nowadays. In C++ and Java also we can get this kind of feature. There are some similarities between exception handling in C++ and exception handling in Java, like in both languages we have to use the try-catch block. Though there are some difficulties also. These are like below −In C++, we can throw any type of data as exception. Any type of data means primitive datatypes and pointers also. In Java we can only throw the throwable objects. Subclasses of any throwable class will also be throwable.Example#include using ...
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