Compilare: user.cpp: In function ‘int main()’: user.cpp:54:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cobai.in", "r", stdin); ^ user.cpp:55:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:60:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &a[i][j]); ^ user.cpp:76:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(dir); ^ /tmp/ccMZr8mX.o: In function `main': user.cpp:(.text.startup+0x11a): warning: the `gets' function is dangerous and should not be used.