grupuri.cpp: In function 'int main()': grupuri.cpp:40: warning: operation on 'cate' may be undefined grupuri.cpp:5: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result grupuri.cpp:6: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result grupuri.cpp:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result grupuri.cpp:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result