View Compilation Error

0_0_17927960_17093.cpp: In function 'void dfs(int, int, ll)':
0_0_17927960_17093.cpp:73:7: error: 'cas' was not declared in this scope
    if(cas^num[i])nsum-=cnt[d][i];
       ^
0_0_17927960_17093.cpp:76:13: error: 'cas' was not declared in this scope
   dfs(d+1,x|cas<<d,nsum);
             ^