View Compilation Error

843373_0_0_21003.cpp:18: error: `N' was not declared in this scope
843373_0_0_21003.cpp: In function `int main()':
843373_0_0_21003.cpp:70: error: `c' undeclared (first use this function)
843373_0_0_21003.cpp:70: error: (Each undeclared identifier is reported only once for each function it appears in.)