Main.cc: In function 'int main()':
Main.cc:9:8: error: 'a' was not declared in this scope
cin>>a[i];
^
Main.cc:12:3: error: 'a' was not declared in this scope
a[i+1]=a[i];
^
Main.cc:14:2: error: 'a' was not declared in this scope
a[1]=x;
^