Main.cc: In function ‘std::__cxx11::string add(std::__cxx11::string, std::__cxx11::string)’: Main.cc:6:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(a.size()>_) a='0'+a; ~~~~~~~~^~ Main.cc:7:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(b.size()>_) b='0'+b; ~~~~~~~~^~ Main.cc: At global scope: Main.cc:17:12: error: conversion from ‘char’ to non-scalar type ‘std::__cxx11::string {aka std::__cxx11::basic_string}’ requested string ans='0',dl; ^~~ Main.cc: In function ‘int main()’: Main.cc:20:22: error: expected primary-expression before ‘)’ token for(int i=k;i<=m;i+=){ ^ Main.cc:22:16: warning: suggest parentheses around assignment used as truth value [-Wparentheses] for(int j=1;j=i-1;j++){ ~^~~~ Main.cc:23:4: error: ‘rs’ was not declared in this scope rs=add(rs,rs); ^~ Main.cc:27:9: error: invalid use of member function ‘std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits; _Alloc = std::allocator; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]’ (did you forget the ‘()’ ?) if(ans.size<=6) cout<