foo.cc: In function 'int main()':
foo.cc:8:8: warning: unused variable 'b' [-Wunused-variable]
    8 |  int i,b=100,num,sum;
      |        ^
foo.cc:16:5: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
   16 |  sum=sum/num;
      |  ~~~^~~~~~~~

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