Compilare: user.cpp: In function ‘int main()’: user.cpp:45:16: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (ok(l1,c1) && !in_q[l1][c1]) ^ user.cpp:56:16: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (ok(l2,c2) && !in_q[l2][c2]) ^ user.cpp:21:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("drum6.in","r",stdin); ^ user.cpp:22:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("drum6.out","w",stdout); ^ user.cpp:24:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:28:34: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,1,m+1,stdin); ^