foo.cc: In function 'int main()':
foo.cc:6:15: error: 'x1' does not name a type
    6 |         const x1<=x2;
      |               ^~
foo.cc:7:25: error: lvalue required as left operand of assignment
    7 |         printf("%d\n",x1+x2=x);
      |                       ~~^~~

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