foo.cc: In function 'int main()':
foo.cc:7:8: warning: statement has no effect [-Wunused-value]
    7 |  for(x1<x/2;x1=x1+2;)
      |      ~~^~~~
foo.cc:7:15: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    7 |  for(x1<x/2;x1=x1+2;)
      |             ~~^~~~~
foo.cc:7:15: warning: 'x1' is used uninitialized in this function [-Wuninitialized]
    7 |  for(x1<x/2;x1=x1+2;)
      |             ~~^~~~~

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