Compilare: user.cpp: In function ‘int main()’: user.cpp:18:9: warning: unused variable ‘ni’ [-Wunused-variable] int ni=a.length(); ^ user.cpp:20:9: warning: unused variable ‘N’ [-Wunused-variable] int N=a.length(),i; ^ user.cpp:20:22: warning: unused variable ‘i’ [-Wunused-variable] int N=a.length(),i; ^ user.cpp:22:9: warning: unused variable ‘st’ [-Wunused-variable] int st=0,dr=0,result=0; ^ user.cpp:22:14: warning: unused variable ‘dr’ [-Wunused-variable] int st=0,dr=0,result=0; ^ user.cpp:22:19: warning: unused variable ‘result’ [-Wunused-variable] int st=0,dr=0,result=0; ^