View Compilation Error

0_0_11556905_6188.cpp: In function `int main()':
0_0_11556905_6188.cpp:34: error: `b' undeclared (first use this function)
0_0_11556905_6188.cpp:34: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_11556905_6188.cpp:35: error: `res' undeclared (first use this function)