traffic.cpp: In function 'void setIO(std::string)':
traffic.cpp:29:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
29 | freopen((name + ".in").c_str(), "r", stdin); // see Input & Output
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
traffic.cpp:30:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
30 | freopen((name + ".out").c_str(), "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
traffic.cpp: In function 'int LocateCentre(int)':
traffic.cpp:73:12: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
73 | return ans;
| ^~~
/tmp/cc6ttvbe.o: In function `main':
grader.cpp:(.text.startup+0xd9): undefined reference to `LocateCentre(int, int*, int*, int*)'
collect2: error: ld returned 1 exit status