Theory:

Political Parties
Political parties are an important part of democracy. Parties are the link between government and the people.
 
Meaning of Political Party
A political party is an organisation formed by a group of people with a certain ideology and agenda to contest elections and hold power in the government.
A political party has three components: A leader, active members and the followers.
  
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In general, there are three major types of the party system.
 
Single Party System: In this type of system, only one political party has the right to form the government. No opposition is permitted in this system.
Example:
Communist countries such as China, North Korea, Cuba and the USSR (Union of Soviet Socialist Republics).
Bi – Party System (Two-party system): In this type of system, the power is usually shared between two parties. Between the two parties, one becomes the ruling party, and the other becomes the opposition.
Example:
U.K. (Labour Party and Conservative Party), U.S.A (Republican Party and Democratic Party).
Multi-Party System: In this type of system, three or more parties compete for power.
Example:
India, France, Sweden and Norway
How is the President of India elected?
The President of India is elected by the members of an electoral college consisting of
1. The elected members of both Houses of Parliament
2. The elected members of the Legislative Assemblies of all the states and Union territories in India
The members nominated to either House of Parliament or the Legislative Assemblies of states are not eligible to be included in the electoral college.