View Compilation Error

0_0_22175108_24471.c: In function 'main':
0_0_22175108_24471.c:21:4: error: unknown type name 'bool'
    bool flag = true;
    ^
0_0_22175108_24471.c:21:16: error: 'true' undeclared (first use in this function)
    bool flag = true;
                ^
0_0_22175108_24471.c:21:16: note: each undeclared identifier is reported only once for each function it appears in
0_0_22175108_24471.c:25:12: error: 'false' undeclared (first use in this function)
     flag = false;
            ^