Notes: Tuesday 29 October 2002

Schedule

• Thursday, October 31: Problem Set 5: Part 2

Subtyping Arrays
What are the advantages of allowing B[] <= A[] when B <= A?

What are the dangers of allowing B[] <= A[] when B <= A?

Abstract Types in C

How can we get the benefits of data abstraction in a language with user-defined types but no abstract data types?

Species.h

typedef /*@abstract@*/ struct {
  /*@only@*/ char *name;
  /*@only@*/ char *genome;
} *Species;

extern /*@only@*/ Species Species_new (/*@only@*/ char *p_name, /*@only@*/ char *p_genome) 
   /* EFFECTS: Returns a new Species with name p_name and genome p_genome. */ ;

extern /*@observer@*/ char *Species_getName (Species s) ;
extern /*@observer@*/ char *Species_getGenome (Species s) ;

extern /*@only@*/ char *Species_toString (Species s)
   /* EFFECTS: Returns a string representation of s. */ ;

Links

• Dennis Ritchie, Development of the C Language
• Dennis Ritchie's home page has links to many interesting resources on C, and a nice story about his trip to the White House to get the 1998 National Medal of Technology
• Splint

University of Virginia Department of Computer Science CS 201J: Engineering Software

Sponsored by the National Science Foundation

cs201j-staff@cs.virginia.edu