The Computer Language
Benchmarks Game

C gcc versus C++ g++ fastest programs

Back in April 2010, Russ Cox charitably suggested that only fannkuch-redux, fasta, k-nucleotide, mandlebrot, nbody, reverse-complement and spectral-norm were close to fair comparisons. As someone who implemented programming languages, his interest was "measuring the quality of the generated code when both compilers are presented with what amounts to the same program."

Differences in approach - to memory management, parallel programming, regex, arbitrary precision arithmetic, implementation technique - don't fit in that kind-of fair comparison — but we still have to deal with them.

These are only the fastest programs. There may be additional measurements for programs which seem more-like a fair comparison to you. Always look at the source code.

regex-redux
source secs mem gz busy cpu load
C gcc 1.46 152,236 1397 3.43 43% 100% 45% 48%
C++ g++ 1.82 203,760 1315 4.43 44% 51% 48% 100%
fannkuch-redux
source secs mem gz busy cpu load
C gcc 8.61 880 910 33.96 95% 100% 99% 100%
C++ g++ 10.08 1,884 980 39.72 100% 100% 99% 95%
n-body
source secs mem gz busy cpu load
C gcc 7.49 8 1391 7.56 0% 0% 100% 1%
C++ g++ 8.18 1,112 1773 8.24 100% 0% 0% 1%
binary-trees
source secs mem gz busy cpu load
C gcc 3.48 168,744 809 11.47 99% 74% 79% 79%
C++ g++ 3.79 117,164 809 12.28 99% 76% 75% 74%
pidigits
source secs mem gz busy cpu load
C gcc 1.75 2,660 452 2.02 1% 100% 14% 1%
C++ g++ 1.89 4,460 513 1.97 100% 2% 2% 1%
spectral-norm
source secs mem gz busy cpu load
C gcc 1.98 1,252 1139 7.88 99% 100% 99% 99%
C++ g++ 1.98 1,268 1044 7.89 100% 99% 99% 99%
fasta
source secs mem gz busy cpu load
C gcc 1.36 2,912 2268 5.42 99% 100% 99% 99%
C++ g++ 1.33 1,824 2711 4.31 82% 82% 81% 80%
mandelbrot
source secs mem gz busy cpu load
C gcc 1.65 26,204 1135 6.56 99% 100% 99% 99%
C++ g++ 1.50 26,324 1791 5.97 100% 99% 99% 99%
reverse-complement
source secs mem gz busy cpu load
C gcc 1.78 994,532 1438 4.02 42% 96% 46% 43%
C++ g++ 1.55 996,188 1226 2.66 24% 25% 99% 23%
k-nucleotide
source secs mem gz busy cpu load
C gcc 5.01 130,104 1506 16.41 84% 100% 84% 59%
C++ g++ 3.76 156,180 1624 11.55 97% 71% 71% 69%
C gcc

gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0

C++ g++

g++ (Ubuntu 8.3.0-6ubuntu1) 8.3.0