View Compilation Error

0_0_28507048_18352.c:6:1: error: unknown type name 'bool'
 bool flag;
 ^
0_0_28507048_18352.c: In function 'main':
0_0_28507048_18352.c:25:16: error: 'true' undeclared (first use in this function)
         flag = true;
                ^
0_0_28507048_18352.c:25:16: note: each undeclared identifier is reported only once for each function it appears in
0_0_28507048_18352.c:32:24: error: 'false' undeclared (first use in this function)
                 flag = false;
                        ^