foo.cc: In function 'int read()':
foo.cc:9:17: warning: 'ch' is used uninitialized [-Wuninitialized]
    9 |     while(ch<'0'||ch>'9')
      |           ~~~~~~^~~~~~~~
foo.cc:15:14: warning: 'f' may be used uninitialized in this function [-Wmaybe-uninitialized]
   15 |     return f*x;
      |              ^

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