The basic structure of a C++ program is shown below:
The first line that begins with “#” is a preprocessor directive. In this case, we are using include as a directive which tells the compiler to include a header while “iostream.h” which will be used for basic input/output later in the program.
The next line is the “main” function that returns an integer. The main function is the starting point of execution for any C++ program. Irrespective of its position in the source code file, the contents of the main function are always executed first by the C++ compiler.
In the next line, we can see open curly braces that indicate the start of a block of code. After this, we see the programming instruction or the line of code that uses the count which is the standard output stream (its definition is present in iostream.h).
This output stream takes a string of characters and prints it to a standard output device. In this case, it is, “Hello, World!”. Please note that each C++ instruction ends with a semicolon (;), which is very much necessary and omitting it will result in compilation errors.
Before closing the braces}, we see another line “return 0;”. This is the returning point to the main function.
Every C++ program will have a basic structure as shown above with a preprocessor directive, main function declaration followed by a block of code and then a returning point to the main function which indicates successful execution of the program.