foo.c: In function 'SetUnion':
foo.c:23:13: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   23 |         if (k = -1)
      |             ^
foo.c: In function 'main':
foo.c:44:14: warning: unknown conversion type character ' ' in format [-Wformat=]
   44 |     scanf(" % d & d % d", &n1, &n2, &n3);
      |              ^
foo.c:44:22: warning: unknown conversion type character ' ' in format [-Wformat=]
   44 |     scanf(" % d & d % d", &n1, &n2, &n3);
      |                      ^
foo.c:44:11: warning: too many arguments for format [-Wformat-extra-args]
   44 |     scanf(" % d & d % d", &n1, &n2, &n3);
      |           ^~~~~~~~~~~~~~
foo.c:58:27: warning: passing argument 2 of 'SetUnion' makes pointer from integer without a cast [-Wint-conversion]
   58 |     int nb = SetUnion(a1, n1, a2, n2, b);
      |                           ^~
      |                           |
      |                           int
foo.c:17:27: note: expected 'int *' but argument is of type 'int'
   17 | int SetUnion(int a[], int b[], int c[], int na, int nb)
      |                       ~~~~^~~
foo.c:58:39: warning: passing argument 5 of 'SetUnion' makes integer from pointer without a cast [-Wint-conversion]
   58 |     int nb = SetUnion(a1, n1, a2, n2, b);
      |                                       ^
      |                                       |
      |                                       int *
foo.c:17:53: note: expected 'int' but argument is of type 'int *'
   17 | int SetUnion(int a[], int b[], int c[], int na, int nb)
      |                                                 ~~~~^~
foo.c:59:27: warning: passing argument 2 of 'SetUnion' makes pointer from integer without a cast [-Wint-conversion]
   59 |     int nc = SetUnion(a1, n1, a3, n3, c);
      |                           ^~
      |                           |
      |                           int
foo.c:17:27: note: expected 'int *' but argument is of type 'int'
   17 | int SetUnion(int a[], int b[], int c[], int na, int nb)
      |                       ~~~~^~~
foo.c:59:39: warning: passing argument 5 of 'SetUnion' makes integer from pointer without a cast [-Wint-conversion]
   59 |     int nc = SetUnion(a1, n1, a3, n3, c);
      |                                       ^
      |                                       |
      |                                       int *
foo.c:17:53: note: expected 'int' but argument is of type 'int *'
   17 | int SetUnion(int a[], int b[], int c[], int na, int nb)
      |                                                 ~~~~^~

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