Compilare: user.cpp: In function ‘void readExpr(FILE*, char*, int&, int&)’: user.cpp:64:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(var[ch] == -1) { ^ user.cpp:65:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] var[ch] = lastvar; ^ user.cpp:68:27: warning: array subscript has type ‘char’ [-Wchar-subscripts] expr[top++] = var[ch]; ^ user.cpp:69:31: warning: array subscript has type ‘char’ [-Wchar-subscripts] col = col | (1 << var[ch]); ^ user.cpp: In function ‘int main()’: user.cpp:107:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d\n", &t); ^