View Compilation Error

0_0_15057916_16019.cpp: In function 'int main()':
0_0_15057916_16019.cpp:4:14: error: 'a' was not declared in this scope
 while(cin >> a >> b) cout << a + b << endl;
              ^
0_0_15057916_16019.cpp:4:19: error: 'b' was not declared in this scope
 while(cin >> a >> b) cout << a + b << endl;
                   ^