discharge of contract ( headings only )

there are six methods to discharge a contract and these methods have more types
1) discharge by performance
    a) actual performance
    b) tender
2) discharge by agreement 
   a) novation
   b) alteration
   c) rescission
   d) remission
   e) waiver
3) discharge by subsequent impossibility 
   a) destruction of subject matter
   b) failure of purpose
   c) death of personal incapacity
   d) change in law
   e) declaration of war 
4) discharge by laps of time
5)  discharge by operation of law 
   a) insolvency
   b) merger
   c) material alteration
6)  discharge by breach of contract 
    a) actual breach
    b) anticipatory breach
    c) express breach
    d) implied breach