View Compilation Error

138291_0_9496.cpp: In function `int main()':
138291_0_9496.cpp:7: error: `i' undeclared (first use this function)
138291_0_9496.cpp:7: error: (Each undeclared identifier is reported only once for each function it appears in.)
138291_0_9496.cpp:7: error: `j' undeclared (first use this function)
138291_0_9496.cpp:9: error: no match for 'operator>>' in 'std::cout >> (a + b)'