View Compilation Error

0_0_39186216_16443.c:5:1: error: unknown type name 'bool'
    5 | bool check(double a,double b,double c)
      | ^~~~
0_0_39186216_16443.c:4:1: note: 'bool' is defined in header '<stdbool.h>'; did you forget to '#include <stdbool.h>'?
    3 | #include <math.h>
  +++ |+#include <stdbool.h>
    4 | double n;