View Compilation Error

220601_0_18835.cpp: In function `int main()':
220601_0_18835.cpp:14: error: stray '\' in program
220601_0_18835.cpp:14: error: `n4' undeclared (first use this function)
220601_0_18835.cpp:14: error: (Each undeclared identifier is reported only once for each function it appears in.)