/in/foo.cc: In function 'int main()':
/in/foo.cc:23:19: error: expected unqualified-id before '[' token
         for (auto [num, f] : freq) {
                   ^
/in/foo.cc:23:19: error: expected ';' before '[' token
/in/foo.cc: In lambda function:
/in/foo.cc:23:28: error: expected '{' before ':' token
         for (auto [num, f] : freq) {
                            ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:23:28: error: could not convert '<lambda closure object>main()::<lambda()>{num, f}' from 'main()::<lambda()>' to 'bool'
/in/foo.cc:23:28: error: expected ';' before ':' token
/in/foo.cc:23:28: error: expected primary-expression before ':' token
/in/foo.cc:23:28: error: expected ')' before ':' token
/in/foo.cc:23:28: error: expected primary-expression before ':' token