View Compilation Error

190361_0_30682.cpp: In function `int main()':
190361_0_30682.cpp:12: error: expected primary-expression before '=' token
190361_0_30682.cpp:13: error: `sum' undeclared (first use this function)
190361_0_30682.cpp:13: error: (Each undeclared identifier is reported only once for each function it appears in.)