View Compilation Error

0_0_13497795_6496.cpp: In function 'int main()':
0_0_13497795_6496.cpp:6:16: error: 'a' was not declared in this scope
     while(cin>>a>>b) {cout<<a+b<<endl;}
                ^
0_0_13497795_6496.cpp:6:19: error: 'b' was not declared in this scope
     while(cin>>a>>b) {cout<<a+b<<endl;}
                   ^