foo.c: In function 'main':
foo.c:6:21: warning: implicit declaration of function 'malloc' [-Wimplicit-function-declaration]
    6 |     int *a = (int *)malloc(sizeof(int) * n);
      |                     ^~~~~~
foo.c:2:1: note: include '<stdlib.h>' or provide a declaration of 'malloc'
    1 | #include <stdio.h>
  +++ |+#include <stdlib.h>
    2 | int main()
foo.c:6:21: warning: incompatible implicit declaration of built-in function 'malloc' [-Wbuiltin-declaration-mismatch]
    6 |     int *a = (int *)malloc(sizeof(int) * n);
      |                     ^~~~~~
foo.c:6:21: note: include '<stdlib.h>' or provide a declaration of 'malloc'
foo.c:35:17: warning: implicit declaration of function 'free' [-Wimplicit-function-declaration]
   35 |                 free(e);
      |                 ^~~~
foo.c:35:17: note: include '<stdlib.h>' or provide a declaration of 'free'
foo.c:35:17: warning: incompatible implicit declaration of built-in function 'free' [-Wbuiltin-declaration-mismatch]
foo.c:35:17: note: include '<stdlib.h>' or provide a declaration of 'free'
foo.c:41:5: warning: incompatible implicit declaration of built-in function 'free' [-Wbuiltin-declaration-mismatch]
   41 |     free(a);
      |     ^~~~
foo.c:41:5: note: include '<stdlib.h>' or provide a declaration of 'free'

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