View Compilation Error

0_0_1443285_14987.c: In function `divide':
0_0_1443285_14987.c:20: error: `bool' undeclared (first use in this function)
0_0_1443285_14987.c:20: error: (Each undeclared identifier is reported only once
0_0_1443285_14987.c:20: error: for each function it appears in.)
0_0_1443285_14987.c:20: error: syntax error before "flag"
0_0_1443285_14987.c:24: error: `flag' undeclared (first use in this function)
0_0_1443285_14987.c:24: error: `false' undeclared (first use in this function)
0_0_1443285_14987.c:29: error: `true' undeclared (first use in this function)