Example 1:
realloc . In Standard C,
realloc is an infamous example of bad design. It has to do too many things: allocate memory if passed
NULL , free it if passed a zero size, reallocate it in place if it can, or move memory around if it cannot. It is not easily extensible. It is widely viewed as a shortsighted design failure.
Example 2:
basic_string . In Standard C++,
std::basic_string is an equally infamous example of monolithic class design. Too many "nice-to-have" features were added to a bloated class that tries to be a container but isn't quite, is undecided on iteration vs. indexing, and gratuitously duplicates many standard algorithms while leaving little space for extensibility. (See Item 44's Example.)