rebus1.cpp: In function 'int main()': rebus1.cpp:63: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result rebus1.cpp:64: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result rebus1.cpp:66: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result rebus1.cpp:67: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result /tmp/ccjufWGd.o: In function `main': rebus1.cpp:(.text+0x241): warning: the `gets' function is dangerous and should not be used.