Compilare: user.cpp: In function ‘int main()’: user.cpp:26:34: warning: operation on ‘i’ may be undefined [-Wsequence-point] f1[s2[i]]=s2[++i]; ^ user.cpp:10:22: warning: variable ‘l1’ set but not used [-Wunused-but-set-variable] int i,j,top=0,l2,l1; ^ user.cpp:21:9: warning: ‘l2’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(l2) ^