foo.c: In function 'gcd':
foo.c:7:1: warning: control reaches end of non-void function [-Wreturn-type]
    7 | }
      | ^
foo.c: In function 'main':
foo.c:11:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   11 |  scanf("%d",&n);
      |  ^~~~~~~~~~~~~~
foo.c:13:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   13 |  scanf("%d",&a[i]);
      |  ^~~~~~~~~~~~~~~~~
foo.c:18:5: warning: array subscript -1 is below array bounds of 'int[10]' [-Warray-bounds]
   18 |   t=gcd(t,a[i]);
      |     ^~~~~~~~~~~
foo.c:9:7: note: while referencing 'a'
    9 | { int a[10];
      |       ^

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