foo.cc: In function ‘int main()’:
foo.cc:18:19: error: expected primary-expression before ‘<’ token
   18 |         {   cout<<<1<<" "<<1<<" "<<2;
      |                   ^
foo.cc:18:21: error: invalid operands of types ‘int’ and ‘const char [2]’ to binary ‘operator<<’
   18 |         {   cout<<<1<<" "<<1<<" "<<2;
      |                    ~^~~~~
      |                    |  |
      |                    |  const char [2]
      |                    int
foo.cc:24:28: error: unable to find numeric literal operator ‘operator""；’
   24 |                         i+=1；
      |                            ^~~
foo.cc:24:28: note: use ‘-fext-numeric-literals’ to enable more built-in suffixes