top.cpp: In function 'int main()': top.cpp:25: warning: NULL used in arithmetic top.cpp:32: warning: NULL used in arithmetic top.cpp:9: warning: unused variable 'nrm' top.cpp:7: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result top.cpp:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result top.cpp:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result top.cpp:14: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result top.cpp:15: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result /tmp/ccgLB7EB.o: In function `main': top.cpp:(.text+0x100): warning: the `gets' function is dangerous and should not be used.