foo.c: In function 'Insert':
foo.c:19:4: error: 'k' undeclared (first use in this function)
  a[k+1]=x;
    ^
foo.c:19:4: note: each undeclared identifier is reported only once for each function it appears in
foo.c: In function 'main':
foo.c:7:8: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  int n;scanf("%d",&n);
        ^~~~~~~~~~~~~~
foo.c:9:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a[i]);
   ^~~~~~~~~~~~~~~~~
foo.c:10:8: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  int x;scanf("%d",&x);
        ^~~~~~~~~~~~~~

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