View Compilation Error

0_0_7627716_17622.cpp: In function `int main()':
0_0_7627716_17622.cpp:82: error: `sum_a' undeclared (first use this function)
0_0_7627716_17622.cpp:82: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_7627716_17622.cpp:82: error: `sum_b' undeclared (first use this function)
0_0_7627716_17622.cpp:82: error: `sum_c' undeclared (first use this function)