foo.cc: In function 'void isflag(int)':
foo.cc:23:43: warning: statement has no effect [-Wunused-value]
  if ((tp==1||tp==3)&&ishigh==false) ishigh==true;
                                     ~~~~~~^~~~~~
foo.cc:24:41: warning: statement has no effect [-Wunused-value]
  if ((tp==2||tp==4)&&islow==false) islow==true;
                                    ~~~~~^~~~~~
foo.cc: In function 'void PAS()':
foo.cc:55:6: error: 'sums' was not declared in this scope
  if (sums==2)
      ^~~~
foo.cc:55:6: note: suggested alternative: 'nums'
  if (sums==2)
      ^~~~
      nums
foo.cc: In function 'void O()':
foo.cc:81:82: warning: suggest parentheses around comparison in operand of '==' [-Wparentheses]
  if ((ishigh==false&&islow==false)||((nowlow==nowhigh)&&((ifhigh!=iflow)||(ifhigh==iflow==false)))) cout<<"No Answer!";
                                                                            ~~~~~~^~~~~~~
foo.cc:82:32: warning: suggest parentheses around comparison in operand of '==' [-Wparentheses]
  if ((nowlow==nowhigh)&&(ifhigh==iflow==true)) cout<<key<<dengyu<<nowhigh;
                          ~~~~~~^~~~~~~

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