Why C++ was designed ?

1. C++ makes programming more enjoyable for serious programmers.
2. C++ is a general-purpose programming language that 

• is a better C
• supports data abstraction    
• supports object-oriented programming

Layout/Structure of C++

                                             

Section 1: Header File Declaration Section

1. Header files used in the program are listed here.
2. Header File provides Prototype declaration for different library functions.
3. We can also include user define header file.
4. Basically all preprocessor directives are written in this section.

Section 2: Global Declaration Section

1. Global Variables are declared here.
2. Global Declaration may include 

• Declaring Structure
• Declaring prototype
• Declaring variable name

Section 3: Class Declaration Section

1. Actually this section can be considered as sub section for the global declaration section.
2. Class declaration and all methods of that class are defined here.

Section 4: Main Function

1. Each and every C++ program always starts with main function.
2. We can create class objects in the main.
3. Operating system call this function automatically.

Section 5: Method Definition Section

1. This is optional section . Generally this method was used in C Programming.