func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, m;   string res[101];   int dx[] = {0, 0, -1, 1};   int dy[] = {-1, 1, 0, 0};   inline bool in(int x, int y) {     if (x < 0 || y < 0 || x >= n || y >= m) return 0;     return 1;   }   int main(int argc, char **argv) {     cin >> n >> m;     for (int i = 0; i <= n - 1; i++) {       cin >> res[i];     }     int c = 1;     for (int i = 0; i <= n - 1; i++) {       c = i % 2;       for (int j = 0; j <= m - 1; j++) {         if (res[i][j] ==  . ) {           if (c)             res[i][j] =  B ;           else             res[i][j] =  W ;         }         if (c == 1)           c = 0;         else           c = 1;       }     }     for (int i = 0; i <= n - 1; i++) cout << res[i] <<   n ;     return 0;   }   