/in/foo.cc: In function 'int main()':
/in/foo.cc:7:5: error: expected initializer before 'cin'
     cin >> n;
     ^~~
/in/foo.cc:8:9: error: 'n' was not declared in this scope
     if (n <= 0 || n >= 10000) {
         ^
/in/foo.cc:13:25: error: 'n' was not declared in this scope
     vector<int> numbers(n);
                         ^
/in/foo.cc:27:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < peaks.size(); ++i) {
                     ~~^~~~~~~~~~~~~~
/in/foo.cc:28:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         cout << peaks[i] << (i < peaks.size() - 1 ? " " : "");
                              ~~^~~~~~~~~~~~~~~~~~