foo.c: In function 'main':
foo.c:4:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
    4 |  scanf("%d",M);
      |         ~^  ~
      |          |  |
      |          |  int
      |          int *
foo.c:4:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    4 |  scanf("%d",M);
      |  ^~~~~~~~~~~~~
foo.c:4:2: warning: 'M' is used uninitialized in this function [-Wuninitialized]
    4 |  scanf("%d",M);
      |  ^~~~~~~~~~~~~

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