ham.cpp: In function 'int main()': ham.cpp:69: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ham.cpp:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ham.cpp:71: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result ham.cpp:72: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result /tmp/ccUN2wMY.o: In function `main': ham.cpp:(.text+0x2cf): warning: the `gets' function is dangerous and should not be used.