links.cpp: In function 'int href(char*, int)': links.cpp:22: warning: NULL used in arithmetic links.cpp:24: warning: NULL used in arithmetic links.cpp: In function 'int main()': links.cpp:81: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result links.cpp:82: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result links.cpp:84: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result /tmp/ccb6TYtm.o: In function `main': links.cpp:(.text+0x3ea): warning: the `gets' function is dangerous and should not be used.