What is difference between Public and Private IP addresses?

Public ip address : visible to all public users  

Private : Limited access use only for company/organization 

By using public IP address we can able to access internet but we cannot access internet using private IP address.

A public IP address is assigned to every computer that connects to the Internet where each IP is unique. In this case, there cannot exist two computers with the same public IP address all over the Internet. The public IP address is assigned to the computer by the Internet Service Provider as soon as the computer is connected to the Internet gateway.

Private IP addresses are used for numbering the computers in a private network including home, school and business LANs in airports and hotels which makes it possible for the computers in the network to communicate with each other.

External and local IP addresses both serve the same purpose, the difference is scope. An external or public IP address is used across the entire Internet to locate computer systems and devices. A local or internal IP address is used inside a private network to locate the computers and devices connected to it.

Public IP Address which assign to any device and connect to internet it's mean you can access through remote site from anywhere because it's unique IP Address.

Private IP Address which only assign local network and access within Network

Public IP are used to communicate worldwide through Internet.

Private IP are used to communicate in internal network i.e. local network.

Public IP's are used for Internet and Private IP's are used in Intranet.

A public IP address is the address that is assigned to a computing device to allow direct access over the Internet. A web server, email server and any server device directly accessible from the Internet are candidate for a public IP address. A public IP address is globally unique, and can only be assigned to an unique device.

A private IP address is the address space allocated by Inter NIC to allow organizations to create their own private network. There are three IP blocks (1 class A,1 class B and1 class C) reserved for a private use.  

private ip with in organisation and public ip with WAN Topology can communicate with each other by NAT  

A Public IP address, which is usually assigned by an ISP, allows network devises access to the internet. These addresses can be routed over the internet. On the other hand, private IP addresses are reserved addresses for internal network (LAN). They can not be routed over the internet, that is, devices assigned these addresses cannot access the internet except using some kind of address translation technology (usually NAT or PAT)

Public IP address is issued by your ISP,

Private IP address is issued by your router to each network device inside your network.