foo.cc: In function ‘int main()’:
foo.cc:17:17: warning: left operand of comma operator has no effect [-Wunused-value]
   17 |         if(a<b) a,b=b,a;
      |                 ^
foo.cc:17:24: warning: right operand of comma operator has no effect [-Wunused-value]
   17 |         if(a<b) a,b=b,a;
      |                        ^