Compilare: user.cpp: In member function ‘int ExpressionSolve::termen()’: user.cpp:49:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( point >= expression.size() ) return 0; ^ user.cpp:53:29: warning: array subscript has type ‘char’ [-Wchar-subscripts] t = var[ ch ]; ^ user.cpp: In member function ‘int ExpressionSolve::solve(int)’: user.cpp:68:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ( point < expression.size() && strchr( op[level], expression[ point ] ) ) ^ user.cpp: In function ‘std::string re_do(std::string&)’: user.cpp:97:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < s.size(); ++i ) ^ user.cpp: In function ‘int main()’: user.cpp:146:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < A.size(); ++i ) ^ user.cpp:150:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < B.size(); ++i ) ^ user.cpp:163:13: warning: unused variable ‘valid’ [-Wunused-variable] int valid = 1; ^