C++ Programming Code Examples
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A generic version of myabs().
/* A generic version of myabs(). */
#include <iostream>
using namespace std;
template <class X> X myabs(X val)
{
return val < 0 ? -val : val;
}
int main()
{
cout << myabs(-10) << '\n'; // integer abs
cout << myabs(-10.0) << '\n'; // double abs
cout << myabs(-10L) << '\n'; // long abs
cout << myabs(-10.0F) << '\n'; // float abs
return 0;
}
A return statement ends the processing of the current function and returns control to the caller of the function. A value-returning function should include a return statement, containing an expression. If an expression is not given on a return statement in a function declared with a non-void return type, the compiler issues an error message. If the data type of the expression is different from the function return type, conversion of the return value takes place as if the value of the expression were assigned to an object with the same function return type.
A C++ template is a powerful feature added to C++. It allows you to define the generic classes and generic functions and thus provides support for generic programming. Generic programming is a technique where generic types are used as parameters in algorithms so that they can work for a variety of data types. We can define a template for a function. For example, if we have an add() function, we can create versions of the add function for adding the int, float or double type values. Where Ttype: It is a placeholder name for a data type used by the function. It is used within the function definition. It is only a placeholder that the compiler will automatically replace this placeholder with the actual data type. class: A class keyword is used to specify a generic type in a template declaration.
The cout is a predefined object of ostream class. It is connected with the standard output device, which is usually a display screen. The cout is used in conjunction with stream insertion operator (<<) to display the output on a console. On most program environments, the standard output by default is the screen, and the C++ stream object defined to access it is cout. The "c" in cout refers to "character" and "out" means "output". Hence cout means "character output". The cout object is used along with the insertion operator << in order to display a stream of characters.
Consider a situation, when we have two persons with the same name, jhon, in the same class. Whenever we need to differentiate them definitely we would have to use some additional information along with their name, like either the area, if they live in different area or their mother's or father's name, etc. Same situation can arise in your C++ applications. For example, you might be writing some code that has a function called xyz() and there is another library available which is also having same function xyz(). Now the compiler has no way of knowing which version of xyz() function you are referring to within your code.
Absolute value. Returns the absolute value of parameter n ( /n/ ). In C++, this function is also overloaded in header <cmath> for floating-point types (see cmath abs), in header <complex> for complex numbers (see complex abs), and in header <valarray> for valarrays (see valarray abs). Basically the abs function evaluates the absolute value of the given value i.e. value after removing all the signs of negative and positive from the number. Which means it will always return a positive number. Function returns the absolute value of n. abs() function - In C the input is of type 'int' whereas in C++ input is of type 'int, long int or long long int'. In C the output is of 'int' type and in C++ the output has the same data type as input.
#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.
Templates are powerful features of C++ which allows us to write generic programs. Similar to function templates, we can use class templates to create a single class to work with different data types. Class templates come in handy as they can make our code shorter and more manageable. A class template starts with the keyword template followed by template parameter(s) inside <> which is followed by the class declaration. T is the template argument which is a placeholder for the data type used, and class is a keyword. Inside the class body, a member variable var and a member function functionName() are both of type T.
A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.
Test if the stack is logically full. Return true if full, false otherwise. Get the "most recently" inserted item in the stack. Does not alter the stack. Return the most recently inserted item
3D array contains three for loops. to initialize and "print three dimensional" array, you have to use three for loops. Third for loop forms 1D array, Second for loop forms 2D array and the
