supertri.cpp: In function 'int main()': supertri.cpp:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result supertri.cpp:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result supertri.cpp:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result supertri.cpp:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result supertri.cpp:18: warning: 'v2' may be used uninitialized in this function supertri.cpp:18: warning: 'v3' may be used uninitialized in this function supertri.cpp:18: warning: 'v1' may be used uninitialized in this function