Compilare: user.cpp: In function ‘int cost(std::string, std::string)’: user.cpp:28:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0 ; i < b.size() ; ++i) ^ user.cpp:31:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( ; i < a.size() ; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:70:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0 ; j <= c.size() ; ++j) ^ user.cpp:73:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 2 ; i <= inString.size() ; ++i) ^ user.cpp:77:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 1 ; j <= c.size() ; ++j) ^