View Compilation Error

0_0_36733839_2250.cpp: In function 'void work()':
0_0_36733839_2250.cpp:74:7: error: 'a' was not declared in this scope
  cin>>a+1;int j=n;
       ^
0_0_36733839_2250.cpp:77:3: error: 'b' was not declared in this scope
   b[j--]=a[i];
   ^
0_0_36733839_2250.cpp:79:23: error: 'b' was not declared in this scope
  for(int i=1;i<=n;i++)b[i+n]=b[i];
                       ^
0_0_36733839_2250.cpp:81:19: error: 'b' was not declared in this scope
  int idx2=getmnid(b,n);
                   ^