Compilare: main.cpp: In function 'void process_op(std::stack<bool>&, std::__cxx11::string)': main.cpp:54:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation] if (op == "NOT") st.push(l); st.push(!r); ^~ main.cpp:54:34: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if' if (op == "NOT") st.push(l); st.push(!r); ^~ main.cpp: In function 'int main()': main.cpp:120:14: warning: array subscript has type 'char' [-Wchar-subscripts] val[c] ^= 1; ^