Compilare: user.cpp: In function ‘void solve()’: user.cpp:68:47: warning: format ‘%c’ expects argument of type ‘int’, but argument 2 has type ‘long int’ [-Wformat=] printf ("%c %ld\n", i + 'a', f [i]); ^ user.cpp:15:13: warning: unused variable ‘n’ [-Wunused-variable] long i, n, semn, j; ^ user.cpp: In function ‘int main()’: user.cpp:73:15: warning: unused variable ‘n’ [-Wunused-variable] long long n, a, b, c; ^ user.cpp:73:18: warning: unused variable ‘a’ [-Wunused-variable] long long n, a, b, c; ^ user.cpp:73:21: warning: unused variable ‘b’ [-Wunused-variable] long long n, a, b, c; ^ user.cpp:73:24: warning: unused variable ‘c’ [-Wunused-variable] long long n, a, b, c; ^ /tmp/cc0rOyZv.o: In function `read()': user.cpp:(.text+0xb): warning: the `gets' function is dangerous and should not be used.