View Compilation Error

0_0_10002443_18819.cpp:6: error: `_Bool' does not name a type
0_0_10002443_18819.cpp: In function `int num_prime(int)':
0_0_10002443_18819.cpp:15: error: `prime' undeclared (first use this function)
0_0_10002443_18819.cpp:15: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_10002443_18819.cpp: In function `int main()':
0_0_10002443_18819.cpp:25: error: `prime' undeclared (first use this function)
0_0_10002443_18819.cpp:28: error: `sqrt' undeclared (first use this function)