TechPrastu | C++ Programing

| Understanding push_back and emplace_back in C++ C++ provides several mechanisms to add elements to its containers, and two often used are push_back and emplace_back . Understanding the difference between these methods can help you write more efficient and expressive code. Let's delve into these concepts with examples to illustrate their usage and benefits.

| In C++, a concrete class is a class that can be instantiated to create objects, while an abstract class cannot be instantiated and typically contains at least one pure virtual function. Here's a simple C++ program to illustrate the difference between a concrete class and an abstract class: #include <iostream> using namespace std; // Abstract Class class AbstractClass { public:     // Pure virtual function     virtual void display() = 0;     // Concrete method     void show() {         cout << "This is a concrete method in an abstract class." << endl;     } }; // Concrete Class class ConcreteClass : public AbstractClass { public:     // Implementation of the pure virtual function     void display() override {         cout << "This is the implementation of the pure virtual function in a concrete class." << endl;     } }; int main() { ...

| In C++, anonymous classes are classes without a name.  These classes are supported by C++ and can be useful in specific situations. Key Characteristics: - No Constructors: Anonymous classes cannot have constructors. - Destructors Allowed: They can, however, have destructors. - Function Limitations: They cannot be passed as arguments to functions or used as return values from functions. Examples to Illustrate Anonymous Classes 1. Creating a Single Object of an Anonymous Class In this example, an anonymous class is created with an object named `obj1`. The scope of `obj1` extends throughout the program, allowing access within the main function. In the main function, `obj1` is used to call member functions of the anonymous class. // CPP program to illustrate the concept of Anonymous Class #include <iostream> using namespace std; // Anonymous Class : Class is not having any name class {     // data member     int i;   public:     void s...

| Mutable data members in C++ are those whose values can be changed at runtime, even if the object they belong to is declared as constant. This is the opposite of constant members, which cannot be modified once they are set. In certain situations, logic may require some data members to be variable while others remain constant. The concept of mutability is especially helpful in managing such classes effectively. Example Here’s a practical example to illustrate the concept: #include <iostream> using namespace std; class Test {    public:       int a;       mutable int b;       Test(int x=0, int y=0) {          a = x;          b = y;       }       void seta(int x=0) {          a = x;       }       void setb(int y=0) {          b = y;       }     ...

| In the world of C++ programming, both inline functions and macros are mechanisms used to optimize code. They are intended to reduce the function call overhead, but they operate in fundamentally different ways. Understanding the differences between them can help in choosing the right tool for the right situation.

| Nameless Temporary Objects in C++: Simplifying Operator Overloading Efficiency is key when working with C++. One technique to reduce code size and simplify object management is to use nameless temporary objects. This approach is beneficial when we want to return an object from a class member function without explicitly creating a new object. What Are Nameless Temporary Objects? Nameless temporary objects are created when we call a constructor and return its value directly without assigning it to a named variable. This technique is handy for operator overloading, such as the pre-increment operator, where we aim to streamline the code. Implementing Pre-Increment Operator Overloading Let's examine an example of using nameless temporary objects to implement the pre-increment operator overloading in C++. Example Program using namespace std; #include <iostream> class Sample { private:     int count; public:     // Default constructor     Sample() : count(...

An initializer list is used to initialize the data members of a class. This list of members to be initialized is specified in the constructor as a comma-separated list, followed by a colon. Here is an example that demonstrates the use of an initializer list to initialize the variables x and y in the Point class. #include<iostream>  using namespace std;     class Point {  private:      int x;      int y;  public:      Point(int i = 0, int j = 0):x(i), y(j) {}       /*  The above use of the Initializer list is optional as the           constructor can also be written as:          Point(int i = 0, int j = 0) {              x = i;              y = j;          }      */              ...

Creating threads in C++11 provides the ability to execute multiple tasks simultaneously, which greatly improves the efficiency and responsiveness of your programs. In this comprehensive guide, we will delve into five different approaches to creating threads using callable objects. Each method will be explained in detail, accompanied by practical examples to illustrate their usage and benefits. By the end of this exploration, you will have a solid understanding of how to effectively manage concurrent execution in your C++11 applications. 1. Function Pointer A function pointer is a straightforward method for creating a thread. You provide a function along with its arguments to the constructor. Example: # include <iostream> # include <thread> // Function to be executed by the thread void fun ( int x) { while (x++ < 15 ) { std::cout << x << std::endl; } } int main () { // Create a thread that runs the function 'fun' with a...

Certainly! Exploring the concepts of shallow and deep copying in C++ is essential for understanding how objects are duplicated. Let's delve into these topics with comprehensive explanations and illustrative examples to clarify their differences and uses. Shallow Copy A shallow copy of an object copies all the member field values. This works fine if the object contains only primitive data types. However, if the object contains pointers to dynamically allocated memory, the shallow copy will copy the pointer values, not the actual data they point to. This means both the original and the copied object will point to the same memory location, which can lead to issues like double deletion or unintended modifications. Example of Shallow Copy # include <iostream> using namespace std; class Box { private : int length; int breadth; int height; int *p; public : // Function that sets the dimensions void set_dimensions ( int length1, int breadth1, ...