Compilare: user.cpp:13:10: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main(void) ^ user.cpp: In function ‘int main()’: user.cpp:19:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<s.length()-1;++j)if(s[j]=='*' && j>0)s.erase(j-1,2),--j; ^ user.cpp:20:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<s.length()-1 && u<1;++j){ ^