sub.cpp: In function 'int main()': sub.cpp:53: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sub.cpp:54: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sub.cpp:55: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sub.cpp:58: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result sub.cpp:63: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sub.cpp:66: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result /tmp/cc9hyN95.o: In function `main': sub.cpp:(.text+0x256): warning: the `gets' function is dangerous and should not be used.