foo.cc: In function 'int main()':
foo.cc:8:6: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  if(n=4)
     ~^~
foo.cc:6:8: warning: unused variable 'i' [-Wunused-variable]
  int n,i,j,k,m;
        ^
foo.cc:6:10: warning: unused variable 'j' [-Wunused-variable]
  int n,i,j,k,m;
          ^
foo.cc:6:12: warning: unused variable 'k' [-Wunused-variable]
  int n,i,j,k,m;
            ^

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