View Compilation Error

0_0_4802243_14037.c: In function `main':
0_0_4802243_14037.c:16: error: `bool' undeclared (first use in this function)
0_0_4802243_14037.c:16: error: (Each undeclared identifier is reported only once
0_0_4802243_14037.c:16: error: for each function it appears in.)
0_0_4802243_14037.c:16: error: syntax error before "flag"
0_0_4802243_14037.c:21: error: `flag' undeclared (first use in this function)
0_0_4802243_14037.c:21: error: `true' undeclared (first use in this function)
0_0_4802243_14037.c:30: error: `false' undeclared (first use in this function)