View Compilation Error

0_0_33294673_21164.cpp: In function 'void output(int)':
0_0_33294673_21164.cpp:19:19: error: 'n' was not declared in this scope
     for(int i=0;i<n;i++)
                   ^
0_0_33294673_21164.cpp:20:34: error: 'pre' was not declared in this scope
       if( (status&(1<<i))!=0 && (pre[status]&(1<<i))==0 )
                                  ^
0_0_33294673_21164.cpp:25:12: error: 'pre' was not declared in this scope
     output(pre[status]);
            ^
0_0_33294673_21164.cpp: In function 'int main()':
0_0_33294673_21164.cpp:35:21: error: 'n' was not declared in this scope
         scanf("%d",&n);
                     ^
0_0_33294673_21164.cpp:51:21: error: 'pre' was not declared in this scope
                     pre[i|(1<<j)]=i;
                     ^