foo.c: In function 'cc':
foo.c:41:12: warning: statement with no effect [-Wunused-value]
   41 |   b[x-1][y]==-1;
      |   ~~~~~~~~~^~~~
foo.c:50:12: warning: statement with no effect [-Wunused-value]
   50 |   b[x+1][y]==-1;
      |   ~~~~~~~~~^~~~
foo.c:59:12: warning: statement with no effect [-Wunused-value]
   59 |   b[x][y-1]==-1;
      |   ~~~~~~~~~^~~~
foo.c:68:12: warning: statement with no effect [-Wunused-value]
   68 |   b[x][y+1]==-1;
      |   ~~~~~~~~~^~~~
foo.c: In function 'main':
foo.c:12:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   12 |     scanf("%d %d",&m,&n);
      |     ^~~~~~~~~~~~~~~~~~~~
foo.c:17:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   17 |    scanf("%d",&a[i][j]);
      |    ^~~~~~~~~~~~~~~~~~~~

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