View Compilation Error

0_0_17156628_9045.c: In function 'main':
0_0_17156628_9045.c:7:2: error: unknown type name 'bool'
  bool flag=false;
  ^
0_0_17156628_9045.c:7:12: error: 'false' undeclared (first use in this function)
  bool flag=false;
            ^
0_0_17156628_9045.c:7:12: note: each undeclared identifier is reported only once for each function it appears in
0_0_17156628_9045.c:18:10: error: 'true' undeclared (first use in this function)
     flag=true;
          ^