root[~]# g++ broma.cpp -o teste
root[~]# time ./teste 
teste while
teste while
teste while
teste while
teste while
teste while
teste while
teste while
teste while
teste while

real    0m0.003s
user    0m0.002s
sys     0m0.001s

root[~]# time ./teste 
teste for
teste for
teste for
teste for
teste for
teste for
teste for
teste for
teste for
teste for

real    0m0.003s
user    0m0.002s
sys     0m0.002s


root[~]# time ./teste 
teste recur
teste recur
teste recur
teste recur
teste recur
teste recur
teste recur
teste recur
teste recur
teste recur

real    0m0.002s
user    0m0.002s
sys     0m0.000s