The difference between sizeof for a struct and the sum of sizeof of each member of that struct is due to byte padding and alignment. Every data type in C/C++ has a alignment requirement. A processor will have processing word length of its architecture. On a 32 bit machine, the processing word size will be 4 bytes or 32 bits. For example, If you have the struct −Example#include using namespace std; struct X {    char b[3];    int c; }; int main() {    char b[3];    int c;    int total = sizeof(b) + sizeof(c);    cout

Copy elision is an optimization implemented by most compilers to prevent extra (potentially expensive) copies in certain situations. So if you have some code that is creating objects not being used or don't have side effects, examplestruct MyStruct {    MyStruct() {}    MyStruct(const MyStruct&) {       std::cout

ReferencesWhen a variable is declared as a reference, it becomes an alternative name for an existing variable.Syntax Type &newname = existing name;InitializationType &pointer; pointer = variable name;PointersPointers are used to store the address of a variable.SyntaxType *pointer;InitializationType *pointer; pointer = variable name;The main differences between references and pointers are -References are used to refer an existing variable in another name whereas pointers are used to store the address of a variable.References cannot have a null value assigned but pointer can.A reference variable can be referenced bypass by value whereas a pointer can be referenced but pass by referenceA reference must ... Read More

An array is a series of elements of the same type placed in contiguous memory locations that can be individually referenced by adding an index to a unique identifier. To use an array in C++, you'll need to declare it first, for example, int arr[10];This declares an array of type int of size 10. This can store 10 integers in contiguous memory. To Refer to any of its element, you need to use the array access operator and provide it the index of the element you want to access. The indexing in C++ array start from 0. So in the ... Read More

In C++, it is faster to process a sorted array than an unsorted array because of branch prediction. In computer architecture, a branch prediction determines whether a conditional branch (jump) in the instruction flow of a program is likely to be taken or not.Let’s take an example −if(arr[i] > 50) {    Do some operation B } else {    Do some operation A }If we run this code for 100 elements in unsorted and sorted order below things will be happened −For sorted array −1, 2, 3, 4, 5, …… 50, 51………100 A, A, A, A, A A, B ... Read More

Undefined behavior is simply behavior that is not defined by the C++ specification. For example, if you have multiple unary increment/decrement operations in an expression like i++ + ++i, they result in behavior that is not defined. This is simply due to the fact that some language constructs are syntactically valid but you can't predict the behavior when the code is run. Another example is the expression: u = (u++);Implementation-defined behavior is behavior unspecified by the specification and left for the implementor to decide and document how the choice is made. In this case, the choice that is made must ... Read More

In C/C++, the main() function is used in the beginning of every program. This returns the program execution status in the operating system. Syntax Following is the syntax of the main() function using C/C++: int main(void); int main(int argc, char *argv[]); Example Below, the C/C++ example shows the usage of the main() return value. C C++ #include int main() { printf("Hello, C World!"); return 0; } Key Points of C Return 0: This is standard for successful execution Non-zero: It indicates error Implicit return: C99 allows omitting return #include int main() { std::cout

The assignment consists of 2 steps, tearing an object's old state and building a new state for it. The destructor is used for the first step and a copy constructor does the second step. Implementing both of these is straightforward. But when overloading the assignment operator, it can become quite difficult to implement. The copy and swap idiom is a solution for the same.This idiom uses the copy-constructor to build a local copy of the data. It then swaps the old data with the new data using the swap function. The temporary copy is then destructed using the destructor. We ... Read More

There are many great profiling tools for profiling C++ programs on Linux. The most widely used tool is Valgrind. It is a programming tool for memory debugging, memory leak detection, and profiling. You can use valgrind by passing the binary to it and setting the tool to callgrind. First generate the binary by compiling the program −$ g++ -o hello.cpp hello Now use valgrind to profile it: $ valgrind --tool=callgrind ./helloThis will generate a file called callgrind.out.x. You can read this file using a tool called kcachegrind.If you're using gcc, you can use the inbuilt profiling tool, gprof. You can ... Read More

There is no one elegant way to iterate the words of a C/C++ string. The most readable way could be termed as the most elegant for some while the most performant for others. I've listed 2 methods that you can use to achieve this. First way is using a stringstream to read words seperated by spaces. This is a little limited but does the task fairly well if you provide the proper checks. example#include #include #include using namespace std; int main() {     string str("Hello from the dark side");     string tmp;         ... Read More