Compares the string builder and numberToString() function as provided by c++utilities with std::stringstream (without reserving stringstream buffer).
The string builder is actually just a fancy syntax for std::string::reserve() making its use more convenient.
Compile and run
g++ -O3 stringbuilder-bench.cpp -o stringbuilder-bench-O3 -Wl,-rpath /lib/path -L /lib/path -lc++utilities ./stringbuilder-bench-O3
Results on my machine
Results with -03:
plus operator: 00:00:19 stringstream: 00:00:16 string builder: 00:00:05 diff (stringstream minus string builder): 00:00:11 factor (stringstream / string builder): 3.2
However, with -O0 4 times slower:
plus operator: 00:00:34 stringstream: 00:00:23 string builder: 00:01:02 diff (stringstream minus string builder): - 00:35:31 factor (stringstream / string builder): 0.370968
Still 2.42 times faster than stringstream with -O2:
plus operator: 00:00:21 stringstream: 00:00:17 string builder: 00:00:07 diff (stringstream minus string builder): 00:00:10 factor (stringstream / string builder): 2.42857
So this basic tests show that string builder is up to 3 times faster when using full optimization and still 2 times faster when using -O2 (default under Arch Linux). However, without optimization it way slower. Results with clang++ were similar.