View Compilation Error

0_0_5497323_6620.cpp: In function `int main()':
0_0_5497323_6620.cpp:40: error: `left' undeclared (first use this function)
0_0_5497323_6620.cpp:40: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5497323_6620.cpp:40: error: `right' undeclared (first use this function)