foo.cc: In function 'int main()':
foo.cc:7:23: error: 'i' was not declared in this scope; did you mean 'iw'?
    7 |  for(int iw=2;iw<=n-1;i++){
      |                       ^
      |                       iw
foo.cc:5:12: warning: unused variable 'iw' [-Wunused-variable]
    5 |  int n,tmd,iw;
      |            ^~
foo.cc:16:8: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result]
   16 |  system("pause");
      |  ~~~~~~^~~~~~~~~

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