foo.cc: In function 'int main()':
foo.cc:9:18: warning: right operand of comma operator has no effect [-Wunused-value]
    9 |         for(i=2,i<x;i++){
      |                 ~^~
foo.cc:9:24: error: expected ';' before ')' token
    9 |         for(i=2,i<x;i++){
      |                        ^
      |                        ;
foo.cc:6:13: warning: unused variable 'x1' [-Wunused-variable]
    6 |         int x1;
      |             ^~
foo.cc:7:13: warning: unused variable 'x2' [-Wunused-variable]
    7 |         int x2;
      |             ^~

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