foo.cc: In function 'int main()':
foo.cc:9:12: error: 'pow' was not declared in this scope
   if (n >= pow(2, i) && n < pow(2, i + 1))
            ^~~
foo.cc:9:12: note: suggested alternative: 'putw'
   if (n >= pow(2, i) && n < pow(2, i + 1))
            ^~~
            putw

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