Language: C++

#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
const int INF=INT_MAX,MOD=1e9+7;



dfs(int r,int q){
	int A;
	int B;
	int C;
	int sono;
	int kazu=0;
	if(q==n){
		if(r!=1)
		count++;
	}

	if(q==n-1){
		kazu=1;
	for(int i1= kazu; i1<9; i1++){
	for(int i2= kazu; i2<9; i2++){
		for(int i3= kazu; i3<9; i3++){
			A = i1;
			B = i2;
			C = i3;
			if(a[q]!='?')
			A = a[q]-'0';
			if(b[q]!='?')
			B = b[q]-'0';
			if(c[q]!='?')
			C = c[q]-'0';

			if((A+B+r)%10 == C){
				sono = (A+B+r)/C;
				dfs(sono,q+1);
			}
		}
	}
	}
	}
}
int main(){
	string a,b,c;
	while(cin>>a>>b>>c&&a!="0"){
		int count =0;
		int n=a.size();
		int math[3][n]; int pattern[3][n];
		reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
		rep(i,n) math[0][i]=a[i]-'0';
		rep(i,n) math[1][i]=b[i]-'0';
		rep(i,n) math[2][i]=c[i]-'0';
		for(int i=0;i<n;i++){
			for(int j=0;)
			if([i]=='?'-'0'){

			}
		}
dfs(0,0);
cout << count << endl;
	}
	return 0;
}


Compiler output:
a.cc:8:1: error: ISO C++ forbids declaration of 'dfs' with no type [-fpermissive]
    8 | dfs(int r,int q){
      | ^~~
a.cc: In function 'int dfs(int, int)':
a.cc:14:15: error: 'n' was not declared in this scope
   14 |         if(q==n){
      |               ^
a.cc:16:22: error: no post-increment operator for type
   16 |                 count++;
      |                      ^~
a.cc:19:15: error: 'n' was not declared in this scope
   19 |         if(q==n-1){
      |               ^
a.cc:27:28: error: 'a' was not declared in this scope
   27 |                         if(a[q]!='?')
      |                            ^
a.cc:29:28: error: 'b' was not declared in this scope
   29 |                         if(b[q]!='?')
      |                            ^
a.cc:31:28: error: 'c' was not declared in this scope
   31 |                         if(c[q]!='?')
      |                            ^
a.cc:42:1: warning: no return statement in function returning non-void [-Wreturn-type]
   42 | }
      | ^
a.cc: In function 'int main()':
a.cc:49:28: error: no match for 'operator+' (operand types are 'std::string' {aka 'std::__cxx11::basic_string<char>'} and 'int')
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                           ~^~
      |                           | |
      |                           | int
      |                           std::string {aka std::__cxx11::basic_string<char>}
In file included from /usr/include/c++/14/bits/stl_algobase.h:67,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:627:5: note: candidate: 'template<class _Iterator> constexpr std::reverse_iterator<_Iterator> std::operator+(typename reverse_iterator<_Iterator>::difference_type, const reverse_iterator<_Iterator>&)'
  627 |     operator+(typename reverse_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:627:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note: candidate: 'template<class _Iterator> constexpr std::move_iterator<_IteratorL> std::operator+(typename move_iterator<_IteratorL>::difference_type, const move_iterator<_IteratorL>&)'
 1798 |     operator+(typename move_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
In file included from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/basic_string.h:3598:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3598 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3598:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3616:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3616 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3616:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'const _CharT*' and 'std::__cxx11::basic_string<char>'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3635:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3635 |     operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3635:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3652:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3652 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3652:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'const _CharT*' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3670:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, _CharT)'
 3670 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3670:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   deduced conflicting types for parameter '_CharT' ('char' and 'int')
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3682:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3682 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3682:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3689:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3689 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3689:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3696:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3696 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3696:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3719:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3719 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3719:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'const _CharT*' and 'std::__cxx11::basic_string<char>'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3726:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3726 |     operator+(_CharT __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3726:5: note:   template argument deduction/substitution failed:
a.cc:49:29: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   49 |                 reverse(a,a+n);reverse(b,b+n);reverse(c,c+n);
      |                             ^
/usr/include/c++/14/bits/basic_string.h:3733:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const _CharT*)'
 3733 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/