foo.c:5:31: error: expected ';', ',' or ')' before '=' token
 int find(int s[],int n,int num=-9999)
                               ^
foo.c: In function 'main':
foo.c:22:8: error: expected identifier or '(' before 'int'
  int n,int i;
        ^~~
foo.c:25:6: error: 'i' undeclared (first use in this function)
  for(i=0;i<n;i++)
      ^
foo.c:25:6: note: each undeclared identifier is reported only once for each function it appears in
foo.c:28:10: warning: implicit declaration of function 'find' [-Wimplicit-function-declaration]
  int max=find(a,n);
          ^~~~
foo.c:23:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ^~~~~~~~~~~~~~

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