Programming Articles - Page 3202 of 3363

C++ has a standard library that contains common functionality you use in building your applications like containers, algorithms, etc. If names used by these were out in the open, for example, if they defined a queue class globally, you'd never be able to use the same name again without conflicts. So they created a namespace, std to contain this change.The using namespace statement just means that in the scope it is present, make all the things under the std namespace available without having to prefix std:: before each of them.While this practice is okay for example code, pulling in the ... Read More

Just because we haven't reached the EOF, doesn't mean the next read will succeed.Consider you have a file that you read using file streams in C++. When writing a loop to read the file, if you are checking for stream.eof(), you're basically checking if the file has already reached eof. So you'd write the code like −Example#include #include using namespace std; int main() {    ifstream myFile("myfile.txt");    string x;        while(!myFile.eof()) {       myFile >> x;       // Need to check again if x is valid or eof       if(x) { ... Read More

The Rule of three is a rule of thumb when using C++. This is kind of a good practice rule that says that If your class needs any ofa copy constructor, an assignment operator, or a destructor, defined explicitly, then it is likely to need all three of them.Why is this? Its because, if your class requires any of the above, it is managing dynamically allocated resources and would likely be needing the other to successfully achieve that. For example, if you require an assignment operator, you would be creating copies of objects currently being copied by reference, hence allocating ... Read More

When you instantiate a template in C++, the compiler creates a new class. This class has all the places where you placed the template arguments replaced with the actual argument you pass to it when using it. For example −template class MyClass {    T foo;    T myMethod(T arg1, T arg2) {       // Impl    } };And somewhere in your program use this class, MyClass x;The compiler creates a new class upon encountering this for every type argument you pass it. For example, if you created 3 objects with different template arguments you'll get 3 classes, ... Read More

Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which may contain data, in the form of attributes; and instructions to do things, in the form of methods.For example, a person is an object which has certain properties such as height, gender, age, etc. It also has certain methods such as move, talk, and so on.ObjectThis is the basic unit of object oriented programming. That is both data and function that operate on data are bundled as a unit called as object.ClassWhen you define a class, you define a blueprint for an object. This doesn't actually ... Read More

The & symbol is used as an operator in C++. It is used in 2 different places, one as a bitwise and operator and one as a pointer address of operator.Bitwise ANDThe bitwise AND operator (&) compares each bit of the first operand to that bit of the second operand. If both bits are 1, the bit is set to 1. Otherwise, the bit is set to 0. Both operands to the bitwise AND operator must be of integral types. Example #include   using namespace std;   int main() {      unsigned short a = 0x5555;      // pattern 0101 ...      unsigned short b = 0xAAAA;      // pattern 1010 ...      cout

As the name suggests, a symbol you declared was not defined by you. This may occur due to many cases. Let's have a look at three of them −You forgot to define the declared name. For example, you declared a function in a file and used it somewhere. But you did not provide its definition. Code −#include void foo(); int main() {    foo(); // Declared but not defined }You defined it but did not use the qualified name. Say you created a class with a method and defined that method but forgot using scope resolution to link that function ... Read More

The C++11 features supported by Intel are available as an official guide in their docs. You can check these features out on https://software.intel.com/en-us/articles/c0x-features-supported-by-intel-c-compiler.

In this tutorial, we will see the methods to stop form submission using JavaScript. Generally, the HTML form by default submitted automatically if we try to perform some operations by using some events. The automatic submission of the form leads the browser to refresh and reload the whole page again, which we don’t want to perform in some cases. So, to perform any operation before submission we need to change the default behavior of the form to prevent it from submission. Following are the methods we can use to stop form submission − Using the "return false" value Using ... Read More

A year that occurs every four years is considered a leap year in the calendar. For example, 2024 is divisible by 4 therefore, it is a leap year. Conditions for a Leap Year To determine whether a given year is a leap year, the following conditions must be met − The year must be divisible by 4. If the year is divisible by 100, it must also be divisible by 400 to qualify as a leap year. If the year is divisible by 100 but not ... Read More