Compilare: main.cpp: In function 'void operand(char)': main.cpp:18:20: warning: array subscript has type 'char' [-Wchar-subscripts] if (priority[ch]==1) { ^ main.cpp:21:25: warning: array subscript has type 'char' [-Wchar-subscripts] else if (priority[ch]==2) { ^ main.cpp:24:25: warning: array subscript has type 'char' [-Wchar-subscripts] else if (priority[ch]==3) { ^ main.cpp:25:52: warning: array subscript has type 'char' [-Wchar-subscripts] while (ops.empty()==0 && priority[ops.top()]==2) { ^ main.cpp:26:37: warning: array subscript has type 'char' [-Wchar-subscripts] v.push_back(no[ops.top()]); ^ main.cpp:33:37: warning: array subscript has type 'char' [-Wchar-subscripts] v.push_back(no[ops.top()]); ^ main.cpp: In function 'int main()': main.cpp:88:33: warning: array subscript has type 'char' [-Wchar-subscripts] v.push_back(no[ops.top()]); ^ main.cpp:91:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<v.size();i++) { ~^~~~~~~~~