Compilare: user.cpp: In function ‘int main()’: user.cpp:54:38: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(u2 && op[u2]!='(' && prec[ch[i]]<prec[op[u2]]) ^ user.cpp:54:51: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(u2 && op[u2]!='(' && prec[ch[i]]<prec[op[u2]]) ^ user.cpp:9:29: 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:10:31: 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:12:23: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(ch+1,1002,stdin); ^ user.cpp:66:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&t); ^ user.cpp:68:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&c); ^