Item 23: Consider alternative libraries.(More Effective C++)
The contrast in performance between iostreams and stdio is just an example, however, it's not the main point. The main point is that different libraries offering similar functionality often feature different performance trade-offs, so once you've identified the bottlenecks in your software (via profiling — see Item 16), you should see if it's possible to remove those bottlenecks by replacing one library with another. If your program has an I/O bottleneck, for example, you might consider replacing iostreams with stdio, but if it spends a significant portion of its time on dynamic memory allocation and deallocation, you might see if there are alternative implementations of operator new and operator delete available (see Item 8 and Item E10). Because different libraries embody different design decisions regarding efficiency, extensibility, portability, type safety, and other issues, you can sometimes significantly improve the efficiency of your software by switching to libraries whose designers gave more weight to performance considerations than to other
