Compilare: user.cpp: In function ‘bool grad2(std::string)’: user.cpp:52:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < s.size() ; i++) ^ user.cpp: In function ‘void solve2(std::string)’: user.cpp:91:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < s.size()){ ^ user.cpp: In function ‘void solve1(std::string)’: user.cpp:153:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < s.size()) ^ user.cpp: In function ‘void solve2(std::string)’: user.cpp:110:42: warning: ‘x1’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(bin_search(1,num,trunc(x1)) && bin_search(1,num,trunc(x2))) ^