Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Server Side Programming Articles
Page 2090 of 2109
I/O Redirection in C++
In C, we can use the freopen() function for redirection purposes. Using this function, we can redirect existing FILE pointer to another stream. The syntax of the freopen is like below:FILE *freopen(const char* filename, const char* mode, FILE *stream)In C++ also, we can do the redirection. In C++, the streams are used. Here we can use our own stream, and also redirect system streams. In C++, there are three types of streams.istream : Stream, that can support input onlyostream : Stream, that can support output onlyiostream : These can be used for input and output.These classes, and file stream classes ...
Read MoreDifference between files written in binary and text mode in C++
Text modeBinary modeIn text mode various character translations are performed i.e;“\r+\f” is converted into “”In binary mode, such translations are not performed.To write in the files:ofstream ofs (“file.txt”);Orofstream ofs;ofs.open(“file.txt”);to write in the files: ofstream ofs(“file.txt”, ios::binary);orofstream ofs;ofs.open(“file.txt”, ios::binary);To add text at the end of the file:Ofstream ofs(“file.txt”, ios::app);orofstream ofs;ofs.open(“file.txt”, ios::app);To add text at the end of the file:Ofstreamofs(“file.txt”, ios::app|ios::binary);or ofstream ofs;ofs.open(“file.txt”, ios::app|ios::binary);To read files:ifstream in (“file.txt”);orifstreamin ; in.open(“file.txt”);To read files: ifstream in (“file.txt”, ios::binary);orifstream in ;in.open(“file.txt”, ios::binary);
Read MoreHow to read file content into istringstream in C++?
Here is a C++ program to read file content into isstringstream in C++.Example#include #include #include using namespace std; int main() { ifstream is("a.txt", ios::binary ); // get length of file: is.seekg (0, std::ios::end); long length = is.tellg(); is.seekg (0, std::ios::beg); // allocate memory: char *buffer = new char [length]; // read data as a block: is.read (buffer,length); // create string stream of memory contents istringstream iss( string( buffer ) ); cout
Read MoreWhat is difference between a pointer and reference parameter in C++?
PointersPointer variables are used to store the address of variable.SyntaxType *pointer;InitializationType *pointer; Pointer=variable name;ReferencesWhen a parameter is declared as reference, it becomes an alternative name for an existing parameter.SyntaxType &newname=existing name;InitializationType &pointer; Pointer=variable name;The main differences between pointers and reference parameters are −References are used to refer an existing variable in another name whereas pointers are used to store address of variable.References cannot have a null value assigned but pointer can.A reference variable can be referenced by pass by value whereas a pointer can be referenced by pass by reference.A reference must be initialized on declaration while it is not ...
Read MoreProper stack and heap usage in C++?
The stack − All variables declared inside the function will take up memory from the stack. So, any local variable inside a function lives on the stack.The heap − This is unused memory of the program and can be used to allocate the memory dynamically when program runs. So If we want something to live longer than the function that declared it, we must allocate it on the heap.Exampleint main() { int a; //get memory allocated on stack. int *ptr=new int[7]; //memory for 7 integers allocated on heap. }The main issue in heap memory is fragmentation whereas memory ...
Read MoreC++ Program for Sum of squares of first n natural numbers?
In this problem we will see how we can get the sum of squares of first n natural numbers. Here we are using one for loop, that runs from 1 to n. In each step we are calculating square of the term and then add it to the sum. This program takes O(n) time to complete. But if we want to solve this in O(1) or constant time, we can use this series formula −AlgorithmsquareNNatural(n)begin sum := 0 for i in range 1 to n, do sum := sum + i^2 done return ...
Read MoreAdvanced C++ with boost library
C++ boost libraries are widely useful library. This is used for different sections. It has large domain of applications. For example, using boost, we can use large number like 264 in C++.Here we will see some examples of boost library. We can use big integer datatype. We can use different datatypes like int128_t, int256_t, int1024_t etc. By using this we can get precision up to 1024 easily.At first we are multiplying two huge number using boost library.Example#include #include using namespace boost::multiprecision; using namespace std; int128_t large_product(long long n1, long long n2) { int128_t ans = (int128_t) n1 * ...
Read MoreDifference between set, multiset, unordered_set, unordered_multiset in C++
Here we will see what are the differences for set, multiset, unordered_set and unordered_multiset in C++. Let us see the properties of them using some example.SetThe properties of set are like belowStores data in sorted orderStores only unique valuesWe can insert or delete data, but cannot change the dataWe can remove more than one element using start and end iteratorWe can traverse using iteratorsSets are implemented using Binary Search TreeNow let us see an exampleExample#include #include using namespace std; main() { int data[15] = {11, 55, 22, 66, 33, 22, 11, 44, 77, 88, 66, 99, 66, 23, 41}; set my_set; for(int i = 0; i
Read MoreC++ Program to Implement the Alexander Bogomolny's UnOrdered Permutation Algorithm for Elements From 1 to N
This is a C++ program to implement the Alexander Bogomolny’s UnOrdered Permutation Algorithm for elements from 1 to NAlgorithmsBegin function AlexanderBogomolny() to implement the Algorithms Arguments: Val[] = an array N = number of elements taken as input. K = level Body of the function: intialize l = -1 l = l+1 Val[k] = l if (l == N) Call function display(Val, N) else ...
Read MoreC++ Program to Implement the Hill Cypher
Based on linear algebra Hill cipher is a polygraphic substitution cipher in cryptography.To encrypt message: The key string and message string are represented as matrix form. They are multiplied then, against modulo 26. The key matrix should have inverse to decrypt the message.To decrypt message: The encrypted message is multiplied by inverse key matrix used for encryption against modulo 26 to get decrypt message.For exampleKey matrix1 0 1 2 4 0 3 5 6Message string ‘ABC’ in matrix form −0 1 2For encryptionAfter multiplying above two matrices we get, 2 4 17Which will be the encrypted message ‘CER’For decryptionInverse of ...
Read More