View Compilation Error

0_0_18588230_8609.cpp: In function 'void init()':
0_0_18588230_8609.cpp:16:12: error: 'a' was not declared in this scope
     memset(a,0,sizeof a);
            ^
0_0_18588230_8609.cpp: In function 'void work()':
0_0_18588230_8609.cpp:34:27: error: 'a' was not declared in this scope
                     if(j>=a[i])
                           ^
0_0_18588230_8609.cpp:40:35: error: 'a' was not declared in this scope
                     if(k>=1 && j>=a[i])
                                   ^
0_0_18588230_8609.cpp: In function 'int main()':
0_0_18588230_8609.cpp:64:43: error: 'a' was not declared in this scope
         for(int i=1;i<=n;i++) scanf("%d",&a[i]);
                                           ^