View Compilation Error

828240_0_0_139.cpp: In function `int main()':
828240_0_0_139.cpp:22: error: `e' undeclared (first use this function)
828240_0_0_139.cpp:22: error: (Each undeclared identifier is reported only once for each function it appears in.)
828240_0_0_139.cpp:22: error: expected `;' before "while"