Compilare: user.cpp: In function ‘bool eval()’: user.cpp:34:49: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(ops.top()!='(' && pr[ops.top()]>=pr[op]){ ^ user.cpp:34:57: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(ops.top()!='(' && pr[ops.top()]>=pr[op]){ ^ user.cpp:53:49: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(ops.top()!='(' && pr[ops.top()]>=pr[op]){ ^ user.cpp:53:57: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(ops.top()!='(' && pr[ops.top()]>=pr[op]){ ^ user.cpp: In function ‘int main()’: user.cpp:77:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.in","r",stdin); ^ user.cpp:78:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.out","w",stdout); ^ user.cpp:86:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str+1); ^ user.cpp:87:15: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(line); sscanf(line,"%d",&n); ^ user.cpp:88:15: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(line); ^ /tmp/ccgu8sDa.o: In function `main': user.cpp:(.text.startup+0x90): warning: the `gets' function is dangerous and should not be used.