Compilare: user.cpp: In function ‘long int cmmdc(long int, long int)’: user.cpp:16:40: warning: left operand of comma operator has no effect [-Wunused-value] if (!b) return a; else return (b, a % b); ^ user.cpp: In function ‘int main()’: user.cpp:31:6: warning: unused variable ‘t’ [-Wunused-variable] int t = 1; ^