83016_0_30191.cpp 83016_0_30191.cpp(2) : error C2871: 'std' : does not exist or is not a namespace 83016_0_30191.cpp(25) : error C2065: 'num' : undeclared identifier 83016_0_30191.cpp(25) : error C2143: syntax error : missing ';' before 'constant'