View Compilation Error

0_0_9029450_1098.cpp: In function `int main()':
0_0_9029450_1098.cpp:14: error: `sum1' undeclared (first use this function)
0_0_9029450_1098.cpp:14: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_9029450_1098.cpp:17: error: `a' undeclared (first use this function)