foo.cc: In function 'int main()':
foo.cc:8:20: warning: format '%f' expects a matching 'double' argument [-Wformat=]
    8 |         printf("%.1f");
      |                 ~~~^
      |                    |
      |                    double
foo.cc:5:17: warning: variable 'b' set but not used [-Wunused-but-set-variable]
    5 |         float a,b;
      |                 ^

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