foo.c: In function 'main':
foo.c:21:2: error: variable-sized object may not be initialized
  int recordarr[cnt]={0}; //定义用来记录素数出现次数的数组
  ^~~
foo.c:21:22: warning: excess elements in array initializer
  int recordarr[cnt]={0}; //定义用来记录素数出现次数的数组
                      ^
foo.c:21:22: note: (near initialization for 'recordarr')
foo.c:5:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ^~~~~~~~~~~~~~

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