foo.cc: In function 'int Mul2(int*, int, int*, int, int*)':
foo.cc:21:6: warning: unused variable 'jw' [-Wunused-variable]
  int jw=0,n=0,i;
      ^~
foo.cc: In function 'int main()':
foo.cc:50:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&n1,&x1);
  ~~~~~^~~~~~~~~~~~~~~~~
foo.cc:51:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&n2,&x2);
  ~~~~~^~~~~~~~~~~~~~~~~

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