View Compilation Error

0_0_7747618_16169.cpp: In function `int main()':
0_0_7747618_16169.cpp:9: error: `flag' undeclared (first use this function)
0_0_7747618_16169.cpp:9: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_7747618_16169.cpp:23: error: expected `;' before "if"