foo.cc: In function ‘bool cmp(cr, cr)’:
foo.cc:10:40: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   10 |         return a.num<b.xb||a.num==b.num&&a.xb<b.xb;
      |                            ~~~~~~~~~~~~^~~~~~~~~~~
foo.cc: In function ‘int main()’:
foo.cc:24:17: warning: ‘p’ may be used uninitialized [-Wmaybe-uninitialized]
   24 |                 if(p==1)
      |                 ^~
foo.cc:23:21: note: ‘p’ was declared here
   23 |                 int p,x;
      |                     ^
foo.cc:29:33: warning: ‘x’ may be used uninitialized [-Wmaybe-uninitialized]
   29 |                                 if(a[i].xb==x)
      |                                 ^~
foo.cc:23:23: note: ‘x’ was declared here
   23 |                 int p,x;
      |                       ^