Compilare: user.cpp: In function ‘void polish(char*, int, char*, int&)’: user.cpp:19:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] stk[++st] = '('; break; ^ user.cpp:21:30: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (stk[st]!='(') ^ user.cpp:23:46: warning: array subscript has type ‘char’ [-Wchar-subscripts] b[m++]=' ', b[m++]=stk[st]; ^ user.cpp:29:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] stk[++st] = a[i]; ^ user.cpp:32:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (st && stk[st]!='(') ^ user.cpp:34:46: warning: array subscript has type ‘char’ [-Wchar-subscripts] b[m++]=' ', b[m++]=stk[st]; ^ user.cpp:37:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] stk[++st] = a[i]; ^ user.cpp:49:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] b[m++]=' ', b[m++]=stk[st]; ^ user.cpp: In function ‘int main()’: user.cpp:97:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.in", "r", stdin); ^ user.cpp:98:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.out", "w", stdout); ^ user.cpp:100:37: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(expr, sizeof(expr), stdin); ^