Compilare: user.cpp: In function ‘int main()’: user.cpp:171:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( IN , "r" , stdin ) ; ^ user.cpp:173:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d %d\n" , &n , &m ) ; ^ user.cpp:174:22: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets ( sir + 1 ) ; ^ user.cpp:179:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d " , &tip ) ; ^ user.cpp:184:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d %c\n" , &a , &lt ) ; ^ user.cpp:192:51: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d %d %d\n" , &a , &b , &c ) ; ^ user.cpp:371:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( OUT , "w" , stdout ) ; ^ /tmp/ccXvj9RG.o: In function `main': user.cpp:(.text.startup+0xf0): warning: the `gets' function is dangerous and should not be used.