foo.cc: In function 'int main()':
foo.cc:5:8: warning: unused variable 'iw' [-Wunused-variable]
    5 |  int n,iw,tmd;
      |        ^~
foo.cc:16:8: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result]
   16 |  system("pause");
      |  ~~~~~~^~~~~~~~~
foo.cc:12:2: warning: 'tmd' may be used uninitialized in this function [-Wmaybe-uninitialized]
   12 |  if(tmd==2)
      |  ^~

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