traffic.cpp: In function 'void setIO(std::string)':
traffic.cpp:14:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
14 | freopen((name+".in").c_str(), "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
traffic.cpp:15:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
15 | freopen((name+".out").c_str(), "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/tmp/ccTldAb5.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/ccv2TGsi.o:traffic.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status