View Compilation Error

0_0_12947939_4501.cpp: In function `int main()':
0_0_12947939_4501.cpp:21: error: `prime' undeclared (first use this function)
0_0_12947939_4501.cpp:21: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_12947939_4501.cpp:25: error: `phi' undeclared (first use this function)