View Compilation Error

0_0_20063897_20272.c:3:1: error: unknown type name 'bool'
 bool judge(int n)
 ^
0_0_20063897_20272.c: In function 'judge':
0_0_20063897_20272.c:6:5: error: unknown type name 'bool'
     bool flag=true;
     ^
0_0_20063897_20272.c:6:15: error: 'true' undeclared (first use in this function)
     bool flag=true;
               ^
0_0_20063897_20272.c:6:15: note: each undeclared identifier is reported only once for each function it appears in
0_0_20063897_20272.c:11:14: error: 'false' undeclared (first use in this function)
         flag=false;
              ^
0_0_20063897_20272.c: In function 'main':
0_0_20063897_20272.c:20:5: error: unknown type name 'bool'
     bool c ;
     ^
0_0_20063897_20272.c:24:11: error: 'true' undeclared (first use in this function)
         c=true;
           ^
0_0_20063897_20272.c:28:26: error: 'false' undeclared (first use in this function)
             if(judge(y)==false)
                          ^