Compilare: user.cpp: In function ‘int main()’: user.cpp:9:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "cifra.in" , "r" , stdin ) ; ^ user.cpp:10:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "cifra.out" , "w" , stdout ) ; ^ user.cpp:11:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d\n" , & n ) ; ^ user.cpp:27:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets ( s ) ; ^ user.cpp:28:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "\n" ) ; ^ /tmp/ccPJobIk.o: In function `main': user.cpp:(.text.startup+0x14d): warning: the `gets' function is dangerous and should not be used.