Aprime minister differs from a president in the following ways:
1. a prime minister holds power as long as parliament is happy with her/him.
2. a president is elected by the general public where a prime minister is the leader of the majoirty party in the house of commons.
3. a prime minister holds office for six years or until his party holds a vote of "no confidence".
4. a president is elected every four years whereas a parliamentary elections are held every five years.
5. a prime minister can be ousted by a vote of "no confidence" by her/his party's parlimentary ministers.