foo.cpp: In function 'int main()':
foo.cpp:8:7: warning: left operand of comma operator has no effect [-Wunused-value]
  for(0<=x,y<=32767)
      ~^~~
foo.cpp:8:19: error: expected ';' before ')' token
  for(0<=x,y<=32767)
                   ^
foo.cpp:8:12: warning: right operand of comma operator has no effect [-Wunused-value]
  for(0<=x,y<=32767)
           ~^~~~~~~
foo.cpp:11:37: error: invalid operands of types 'int' and '<unresolved overloaded function type>' to binary 'operator<<'
  cout << "the sum is =>" << sum=x+y << endl;
                                 ~~~~^~~~~~~
foo.cpp:11:34: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
  cout << "the sum is =>" << sum=x+y << endl;
                                 ~^~
foo.cpp:12:35: error: expected ')' before ';' token
     cout << "hello, world" << endl;
                                   ^