C++ Programming Code Examples
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Output a string with copy function
/* Output a string with copy function */
#include <algorithm>
#include <iostream>
#include <iterator>
#include <string>
#include <vector>
using namespace std;
int main( )
{
string s( "this is a test." );
cout << s << endl;
copy( s.begin(), s.end(), ostream_iterator<char>( cout, " " ) );
}
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.
Return iterator to end. Returns an iterator pointing to the past-the-end character of the string. The past-the-end character is a theoretical character that would follow the last character in the string. It shall not be dereferenced. Because the ranges used by functions of the standard library do not include the element pointed by their closing iterator, this function is often used in combination with string::begin to specify a range including all the characters in the string. If the object is an empty string, this function returns the same as string::begin.
copy() function is used to copy items from one iterator to another iterator with a specific range. We can define the start and end position of the source and it will copy all items in this rage to a different destination. To use copy() function, we need to include <bits/stdc+.h> or header file. It copies all the elements pointed by first and last. first element is included in the output but last is not. output is the start position of the final result iterator. It returns one iterator to the end of the destination range where elements have been copied. Function returns an iterator to the end of the destination range where elements have been copied.
Strings are objects that represent sequences of characters. The standard string class provides support for such objects with an interface similar to that of a standard container of bytes, but adding features specifically designed to operate with strings of single-byte characters. The string class is an instantiation of the basic_string class template that uses char (i.e., bytes) as its character type, with its default char_traits and allocator types. Note that this class handles bytes independently of the encoding used: If used to handle sequences of multi-byte or variable-length characters (such as UTF-8), all members of this class (such as length or size), as well as its iterators, will still operate in terms of bytes (not actual encoded characters).
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.
Ostream iterators are output iterators that write sequentially to an output stream (such as cout). They are constructed from a basic_ostream object, to which they become associated, so that whenever an assignment operator (=) is used on the ostream_iterator (dereferenced or not) it inserts a new element into the stream. Optionally, a delimiter can be specified on construction. This delimiter is written to the stream after each element is inserted.
Return iterator to beginning. Returns an iterator pointing to the first character of the string. This function gives a reference to the first element. The C++ string::begin function returns the iterator pointing to the first character of the string. Note that, Unlike the string::front function, which returns a direct reference to the first character, it returns the iterator pointing to the same character of the string. This function does not return any value.
Iterators are just like pointers used to access the container elements. Iterators are one of the four pillars of the Standard Template Library or STL in C++. An iterator is used to point to the memory address of the STL container classes. For better understanding, you can relate them with a pointer, to some extent. Iterators act as a bridge that connects algorithms to STL containers and allows the modifications of the data present inside the container. They allow you to iterate over the container, access and assign the values, and run different operators over them, to get the desired result. • Iterators are used to traverse from one element to another element, a process is known as iterating through the container. • The main advantage of an iterator is to provide a common interface for all the containers type. • Iterators make the algorithm independent of the type of the container used.
#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.
A 'while loop' is used and will terminate when user will press esc key. To get the characters a function 'getche()' is used from conio.h which will store in 'char variable' & store into the file
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C++ Program to display 'such a Pattern'. Each row will contain odd numbers of number. The first and last number of each row will be 1 and middle column will be the "row number". So n
