foo.c: In function 'main':
foo.c:6:13: error: redeclaration of 'b' with no linkage
    6 |         int b=1;
      |             ^
foo.c:5:15: note: previous declaration of 'b' with type 'int'
    5 |         int a,b,c,n,num;
      |               ^
foo.c:7:13: error: redeclaration of 'c' with no linkage
    7 |         int c=1;
      |             ^
foo.c:5:17: note: previous declaration of 'c' with type 'int'
    5 |         int a,b,c,n,num;
      |                 ^
foo.c:9:17: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
    9 |         scanf("%d",n);
      |                ~^  ~
      |                 |  |
      |                 |  int
      |                 int *

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