Compilare: user.cpp: In function ‘int main()’: user.cpp:19:13: warning: right operand of comma operator has no effect [-Wunused-value] fin >> a, b; ^ user.cpp:13:23: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] return euclid(b, a%b); ^ user.cpp:18:9: note: ‘b’ was declared here int a, b; ^