Compilare: user.cpp: In function ‘int main()’: user.cpp:42:33: 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:43:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( OUT , "w" , stdout ) ; ^ user.cpp:44:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &t ) ; ^ user.cpp:49:37: 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:52:26: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets ( sir ) ; ^ /tmp/ccCzrmO9.o: In function `main': user.cpp:(.text.startup+0xc1): warning: the `gets' function is dangerous and should not be used.