answer.code: In function ‘void mian()’:
answer.code:42:29: error: no match for ‘operator=’ (operand types are ‘stans’ and ‘<brace-enclosed initializer list>’)
   42 |         anst = { ppd(sp,tp) }; anst.add(0, sp);
      |                             ^
answer.code:27:8: note: candidate: ‘stans& stans::operator=(const stans&)’
   27 | struct stans {
      |        ^~~~~
answer.code:27:8: note:   no known conversion for argument 1 from ‘<brace-enclosed initializer list>’ to ‘const stans&’
answer.code:27:8: note: candidate: ‘stans& stans::operator=(stans&&)’
answer.code:27:8: note:   no known conversion for argument 1 from ‘<brace-enclosed initializer list>’ to ‘stans&&’