transfer.cpp: In function 'std::vector<int> get_attachment(std::vector<int>)':
transfer.cpp:13:16: warning: '<<' in boolean context, did you mean '<'? [-Wint-in-bool-context]
13 | if (j && (1 << i)) {
| ~~~^~~~~
transfer.cpp: In function 'std::vector<int> retrieve(std::vector<int>)':
transfer.cpp:31:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
31 | for (int i = 0; i < extra.size() - 1; i++) Xor ^= extra[i];
| ~~^~~~~~~~~~~~~~~~~~
transfer.cpp:36:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
36 | for (int j = 1; j <= data.size() - extra.size(); j++) {
| ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
transfer.cpp:37:16: warning: '<<' in boolean context, did you mean '<'? [-Wint-in-bool-context]
37 | if (j && (1 << i)) {
| ~~~^~~~~
transfer.cpp:44:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
44 | for (int i = 0; i < extra.size(); i++) cur |= (1 << i) * extra[i];
| ~~^~~~~~~~~~~~~~
/usr/bin/ld: /tmp/cclcPswZ.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccrtsk2X.o:transfer.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status