View Compilation Error

0_0_36592503_25547.cpp: In function 'int main()':
0_0_36592503_25547.cpp:20:32: error: expected initializer before '==' token
         int n, x, ans = 0, sum == 0;
                                ^
0_0_36592503_25547.cpp:25:13: error: 'sum' was not declared in this scope
             sum += x;
             ^
0_0_36592503_25547.cpp:28:46: error: 'sum' was not declared in this scope
         cout << "Case #" << i << ": " << min(sum / 2, (sum - ans) * 2 + 1) << endl;
                                              ^