/in/foo.c:2:1: error: unknown type name 'using'
    2 | using namespace std;
      | ^~~~~
/in/foo.c:2:17: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'std'
    2 | using namespace std;
      |                 ^~~
/in/foo.c:6:1: error: unknown type name 'bool'
    6 | bool map[20001]={false};
      | ^~~~
/in/foo.c:2:1: note: 'bool' is defined in header '<stdbool.h>'; did you forget to '#include <stdbool.h>'?
    1 | #include<stdio.h>
  +++ |+#include <stdbool.h>
    2 | using namespace std;
/in/foo.c:6:18: error: 'false' undeclared here (not in a function)
    6 | bool map[20001]={false};
      |                  ^~~~~
/in/foo.c:6:18: note: 'false' is defined in header '<stdbool.h>'; did you forget to '#include <stdbool.h>'?
/in/foo.c:8:1: error: unknown type name 'bool'
    8 | bool ok[20001];
      | ^~~~
/in/foo.c:8:1: note: 'bool' is defined in header '<stdbool.h>'; did you forget to '#include <stdbool.h>'?
/in/foo.c: In function 'yuchuli':
/in/foo.c:18:21: error: 'true' undeclared (first use in this function)
   18 | ok[make(nowx,nowy)]=true;
      |                     ^~~~
/in/foo.c:18:21: note: 'true' is defined in header '<stdbool.h>'; did you forget to '#include <stdbool.h>'?
/in/foo.c:18:21: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c: In function 'main':
/in/foo.c:61:28: error: 'true' undeclared (first use in this function)
   61 | if (u=='O') map[make(i,j)]=true;
      |                            ^~~~
/in/foo.c:61:28: note: 'true' is defined in header '<stdbool.h>'; did you forget to '#include <stdbool.h>'?