C++ Articles - Page 708 of 719

Auto is a keyword in C++11 and later that is used for automatic type deduction. Type inference or deduction refers to the automatic detection of the data type of an expression in a programming language. It is a feature present in some strongly statically typed languages. For example, you want to create an iterator to iterate over a vector, you can simply use auto for that purpose. example#include #include using namespace std; int main() {    vector arr(10);    for(auto it = arr.begin(); it != arr.end(); it ++) {       cin >> *it;    }    return 0; }In ... Read More

You can initialize a variable using the assignment operator or use its constructor when initializing it. For example,int i = 0; MyClass instance(1, "Hello");It will be automatically initialized ifIt's a class/struct instance in which the default constructor initializes all primitive types; like MyClass instance; You use array initializer syntax, e.g. int a[10] = {} (all zeroed) or int a[10] = {1,2}; (all zeroed except the first two items: a[0] == 1 and a[1] == 2) It is a global/extern variable It is defined static

Type inference (or type deduction) refers that the compiler can figure out the datatype of a variable or expression automatically, without the programmer needing to write it out. This feature is available in many strongly typed languages like C++, where the type system is strict but the compiler helps to reduce the typing effort. Following is the simple example to understand the type deduction in C++. #include using namespace std; int main() { // Let the compiler deduce the type from the value auto number = 50; // int auto pi = 3.14; // double cout

If you have statements like −Class Person;This is a forward declaration. It lets the following code know that there is are classes with the name Person. This satisfies the compiler when it sees these names used. Later the linker will find the definition of the classes.

In C++, declaration and definition are often confused. A declaration tells the compiler about the name and type, while a definition allocates memory or provides implementation. In this article, we will understand their differences with examples. What is a Declaration in C++? A declaration means (in C or C++) that you are telling the compiler about type, size and in case of function declaration, type and size of its parameters of any variable, or user-defined type or function in your program. No space is reserved in memory for any variable in case of the declaration. Following is the syntax to ... Read More

In C++, declaration and definition are often confused. A declaration means (in C) that you are telling the compiler about type, size and in case of function declaration, type and size of its parameters of any variable, or user-defined type or function in your program. No space is reserved in memory for any variable in case of a declaration.The Definition on the other hand means that in additions to all the things that declaration does, space is additionally reserved in memory. You can say "DEFINITION = DECLARATION + SPACE RESERVATION".Following are examples of declarations −extern int a;       ... Read More

An enumerated type declares an optional type name and a set of zero or more identifiers that can be used as values of the type. Each enumerator is a constant whose type is the enumeration. For example, if you are creating an application that has a fixed number of types for some variable. For example, let's say gender, it can be of three types male, female and others. You can define and use an enum like −#include using namespace std; enum Gender {MALE, FEMALE, OTHERS}; int main() {    Gender gen = Gender.FEMALE;    return 0; }By default, the value ... Read More

The equality operators in C++ are is equal to(==) and is not equal to(!=). They do the task as they are named. The binary equality operators compare their operands for strict equality or inequality. The equality operators, equal to (==) and not equal to (!=), have lower precedence than the relational operators, but they behave similarly. The result type for these operators is bool.The equal-to operator (==) returns true (1) if both operands have the same value; otherwise, it returns false (0). The not-equal-to operator (!=) returns true if the operands do not have the same value; otherwise, it returns ... Read More

An enumerated type declares an optional type name and a set of zero or more identifiers that can be used as values of the type. Each enumerator is a constant whose type is the enumeration. For example, if you are creating an application that has a fixed number of types for some variable. For example, let's say gender, it can be of three types male, female and others. You can define and use an enum like −#include using namespace std; enum Gender {MALE, FEMALE, OTHERS}; int main() {    Gender gen = Gender.FEMALE;    return 0; }By default, the value ... Read More

In C++, operators are special symbols that are designed to perform various Operations on variables and values, like arithmetic, comparison, or logical operations. A Postfix Operator is a type of operator that is used to increment or decrement a value by 1(unless overloaded). It is a unary operator, which works only on a single variable. There are two types of postfix operators in C++: ++ : Post-increment -- : Post-decrement Post Increment Operator (++) The post-increment operator increments the value of a given variable by 1, but only after its ... Read More