View Compilation Error

0_0_22188412_20012.cpp: In function 'int main()':
0_0_22188412_20012.cpp:52:8: error: 'a' was not declared in this scope
   sort(a,a+n);
        ^
0_0_22188412_20012.cpp:52:13: error: 'sort' was not declared in this scope
   sort(a,a+n);
             ^