Compilare: user.cpp: In function ‘int main()’: user.cpp:7:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spider.in","r",stdin); ^ user.cpp:8:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spider.out","w",stdout); ^ user.cpp:10:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&m,&n); ^ user.cpp:12:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(j=1;j<=n;++j) scanf("%d",&mat[i][j]); ^ user.cpp:78:26: warning: ‘y’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(mat[l+dx[k]][c+dy[k]]>minn && mat[l+dx[k]][c+dy[k]]<=mat[l][c] && !(l+dx[k]==ll && c+dy[k]==cc) ) { dir=k; minn=mat[l+dx[k]][c+dy[k]]; } ^ user.cpp:78:17: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(mat[l+dx[k]][c+dy[k]]>minn && mat[l+dx[k]][c+dy[k]]<=mat[l][c] && !(l+dx[k]==ll && c+dy[k]==cc) ) { dir=k; minn=mat[l+dx[k]][c+dy[k]]; } ^ user.cpp:78:106: warning: ‘cc’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(mat[l+dx[k]][c+dy[k]]>minn && mat[l+dx[k]][c+dy[k]]<=mat[l][c] && !(l+dx[k]==ll && c+dy[k]==cc) ) { dir=k; minn=mat[l+dx[k]][c+dy[k]]; } ^ user.cpp:78:75: warning: ‘ll’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(mat[l+dx[k]][c+dy[k]]>minn && mat[l+dx[k]][c+dy[k]]<=mat[l][c] && !(l+dx[k]==ll && c+dy[k]==cc) ) { dir=k; minn=mat[l+dx[k]][c+dy[k]]; } ^