View Compilation Error

89211_0_28253.cpp: In function `int main()':
89211_0_28253.cpp:11: error: `n' undeclared (first use this function)
89211_0_28253.cpp:11: error: (Each undeclared identifier is reported only once for each function it appears in.)
89211_0_28253.cpp:18: error: `flag' undeclared (first use this function)