View Compilation Error

0_0_16913414_11499.cpp: In function 'int fact(int)':
0_0_16913414_11499.cpp:5:5: error: 'memo' was not declared in this scope
  if(memo[n]!=0) return memo[n];
     ^
0_0_16913414_11499.cpp:6:9: error: 'memo' was not declared in this scope
  return memo[n]=(a*fact(n-1)+b*fact(n-2))%7;
         ^
0_0_16913414_11499.cpp:6:18: error: 'a' was not declared in this scope
  return memo[n]=(a*fact(n-1)+b*fact(n-2))%7;
                  ^
0_0_16913414_11499.cpp:6:30: error: 'b' was not declared in this scope
  return memo[n]=(a*fact(n-1)+b*fact(n-2))%7;
                              ^