foo.cc: In function ‘int pdrun(int)’:
foo.cc:10:26: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   10 |         return a%400||a%4&&a%100!=0;
      |                       ~~~^~~~~~~~~~
foo.cc: In function ‘int main()’:
foo.cc:48:64: warning: operation on ‘xb_2’ may be undefined [-Wsequence-point]
   48 |                 if (i==1||i==4||i==6||i==8||i==9) flag=0,serch[++xb_2]=serch[xb_2-1]+i;
      |                                                                ^~~~~~
foo.cc:48:64: warning: operation on ‘xb_2’ may be undefined [-Wsequence-point]
foo.cc:49:74: warning: operation on ‘xb_2’ may be undefined [-Wsequence-point]
   49 |                 else if(i%10!=1&&i%10!=3&&i%10!=7&&i%10!=9) flag=0,serch[++xb_2]=serch[xb_2-1]+i;
      |                                                                          ^~~~~~
foo.cc:49:74: warning: operation on ‘xb_2’ may be undefined [-Wsequence-point]
foo.cc:56:47: warning: operation on ‘xb_2’ may be undefined [-Wsequence-point]
   56 |                                         serch[++xb_2]=serch[xb_2-1]+i;
      |                                               ^~~~~~
foo.cc:56:47: warning: operation on ‘xb_2’ may be undefined [-Wsequence-point]
foo.cc:62:33: warning: operation on ‘xb_2’ may be undefined [-Wsequence-point]
   62 |                 if (flag) serch[++xb_2]=serch[xb_2-1];
      |                                 ^~~~~~
foo.cc:62:33: warning: operation on ‘xb_2’ may be undefined [-Wsequence-point]