Compilare: main.cpp: In function 'int main()': main.cpp:19:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:12:11: warning: unused variable 'n' [-Wunused-variable] int a,n; ^ main.cpp:44:19: warning: iteration 29 invokes undefined behavior [-Waggressive-loop-optimizations] if(f[i]) ~~~^ main.cpp:42:22: note: within this loop for(int i=1;i<=30;i++) ~^~~~ main.cpp:18:17: warning: iteration 28 invokes undefined behavior [-Waggressive-loop-optimizations] f[i]=0; ~~~~^~ main.cpp:17:22: note: within this loop for(int i=2;i<=30;i++) ~^~~~