Compilare: user.cpp: In function ‘void Euler(int, int)’: user.cpp:48:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a[k].size(); i++) ^ user.cpp:44:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^ user.cpp: In function ‘int main()’: user.cpp:86:13: warning: unused variable ‘d’ [-Wunused-variable] int i,x,d,sol,y; ^ user.cpp:86:15: warning: unused variable ‘sol’ [-Wunused-variable] int i,x,d,sol,y; ^