Module 3: Structure

• The C++ language defines several headers, which contain information that is either necessary or useful to your program. For this program, the header <iostream> is needed.
• The line using namespace std; tells the compiler to use the std namespace. Namespaces are a relatively recent addition to C++.
• The line int main() is the main function where program execution begins.
• The next line cout << "Hello World"; causes the message "Hello World" to be displayed on the screen.
• The next line return 0; terminates main( )function and causes it to return the value 0 to the calling process.
• The << operator, called the insertion operator, is used to send information to the output stream.
• The >> operator, called the extraction operator, is used to get information from the input stream.
• Strings are used for storing text.
• To use strings, you must include an additional header file in the source code, the <string> library:
• The + operator can be used between strings to add them together to make a new string. This is called concatenation:

  
• A string in C++ is actually an object, which contain functions that can perform certain operations on strings. For example, you can also concatenate strings with the append() function:

  
• It is possible to use the extraction operator >> on cin to display a string entered by a user: