Compilare: user.cpp: In function ‘int main()’: user.cpp:21:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i <= s.length() ; ++i ) ^ user.cpp:25:16: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if ( s[i] != ')' && s[i] != '(' && s[i] != ',') ^ user.cpp:36:16: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if ( s[i] != ')' && s[i] != '(' && s[i] != ',') ^ user.cpp:56:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int j = 1; j < V.size(); ++j ) ^ user.cpp:75:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < V2.size(); ++i ) ^ user.cpp:76:26: warning: NULL used in arithmetic [-Wpointer-arith] if ( V2[i][0] == NULL) ^ user.cpp:79:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < V2.size(); ++i ) ^ user.cpp:80:26: warning: NULL used in arithmetic [-Wpointer-arith] if ( V2[i][0] != NULL) ^