TCP is a protocol based on a connection between two 
computers. It is used for normal Internet traffic and 
applications such as web servers, FTP, etc.

UDP is a protocol based on connectionless communication. 

UDP is ideal for applications like video streaming and 
online gaming, where lost packets don't need to bre 
retransmitted and speed takes precedence.

TCP/IP is a two-way communication between the client and the
server and it is a reliable and there is a confirmation
regarding reaching the message to the destination.it is like
a phone call.
  UDP is a one-way communication only between the client and
the server and it is not a reliable and there is no
confirmation regarding reaching the message to the
destination. it is like a postal mail.

tcp/ip protocol is reliable one .The acknoledgement is 
maintained here.Loss of data can be regained with the help 
of acknowledgement.Udp protocol is unreliable no 
acknowlwdgement is mainted here mainly speed factor plays a 
dominet role. No regain of lost data takes place