func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<string> numbers;   unsigned n = 2;   unsigned k = 5;   int taken[100];   void print(unsigned i) {     unsigned l;     string str =   ;     for (l = 0; l <= i - 1; l++) str += (taken[l] + 1) +  0 ;     numbers.push_back(str);   }   void variate(unsigned i) {     unsigned j;     if (i >= k) {       print(i);       return;     }     for (j = 0; j < n; j++) {       taken[i] = j;       variate(i + 1);     }   }   int main(void) {     for (unsigned i = 1; i < 11; i++) {       k = i;       variate(0);     }     string input;     cin >> input;     for (int i = 0; i < input.size(); i++) {       if (input[i] ==  4 )         input[i] =  1 ;       else         input[i] =  2 ;     }     for (int i = 0; i < numbers.size(); i++) {       if (numbers[i] == input) cout << i + 1 << endl;     }     return 0;   }   