View Compilation Error

0_0_31639136_2778.cpp: In function 'int main()':
0_0_31639136_2778.cpp:6:35: error: 'a' was not declared in this scope
 for(int i=1;i<=n;i++) scanf("%d",&a[i]);
                                   ^
0_0_31639136_2778.cpp:7:6: error: 'a' was not declared in this scope
 sort(a+1,a+n+1);
      ^