View Compilation Error

0_0_13942246_3790.c:4:1: error: unknown type name 'bool'
 bool find(int tag){
 ^
0_0_13942246_3790.c: In function 'find':
0_0_13942246_3790.c:9:32: error: 'true' undeclared (first use in this function)
   if(su[middle] == tag) return true;
                                ^
0_0_13942246_3790.c:9:32: note: each undeclared identifier is reported only once for each function it appears in
0_0_13942246_3790.c:17:9: error: 'false' undeclared (first use in this function)
  return false; 
         ^