traffic.cpp: In function 'void setIO(std::string)':
traffic.cpp:14:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
14 | freopen((s+".in").c_str(),"r",stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
traffic.cpp:15:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
15 | freopen((s+".out").c_str(),"w",stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/tmp/cc4GO54H.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/ccCYUKNw.o:traffic.cpp:(.text.startup+0x0): first defined here
/tmp/cc4GO54H.o: In function `main':
grader.cpp:(.text.startup+0xd9): undefined reference to `LocateCentre(int, int*, int*, int*)'
collect2: error: ld returned 1 exit status