View Compilation Error

851064_0_0_18651.cpp:37: error: `main' must return `int'
851064_0_0_18651.cpp: In function `int main(...)':
851064_0_0_18651.cpp:76: error: `plus' undeclared (first use this function)
851064_0_0_18651.cpp:76: error: (Each undeclared identifier is reported only once for each function it appears in.)