foo.c: In function 'main':
foo.c:3:10: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
 int n,i; scanf("%d", &n);
          ^~~~~
foo.c:3:10: warning: incompatible implicit declaration of built-in function 'scanf'
foo.c:3:10: note: include '<stdio.h>' or provide a declaration of 'scanf'
foo.c:12:7: warning: implicit declaration of function 'ss' [-Wimplicit-function-declaration]
    d= ss(d, y);
       ^~
foo.c:16:2: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
  printf("%d\n", d);
  ^~~~~~
foo.c:16:2: warning: incompatible implicit declaration of built-in function 'printf'
foo.c:16:2: note: include '<stdio.h>' or provide a declaration of 'printf'

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