Compilare: user.cpp: In function ‘void read()’: user.cpp:47:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:50:13: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(c); ^ user.cpp: In function ‘int main()’: user.cpp:68:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("map.in", "r", stdin); ^ user.cpp:69:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("map.out", "w", stdout); ^ /tmp/ccD0y3dm.o: In function `read()': user.cpp:(.text+0x48): warning: the `gets' function is dangerous and should not be used.