foo.cc: In function 'double zhi()':
foo.cc:6:17: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[1]' [-Wformat=]
    6 |         scanf("%s",&ch);
      |                ~^  ~~~
      |                 |  |
      |                 |  char (*)[1]
      |                 char*

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