View Compilation Error

0_0_19308124_12734.cpp: In function 'int main()':
0_0_19308124_12734.cpp:17:48: error: 'a' was not declared in this scope
         for(int i = 0; i < n; i++) scanf("%d", a+i);
                                                ^
0_0_19308124_12734.cpp:18:48: error: 'b' was not declared in this scope
         for(int i = 0; i < n; i++) scanf("%d", b+i);
                                                ^
0_0_19308124_12734.cpp:19:14: error: 'a' was not declared in this scope
         sort(a, a+n);
              ^
0_0_19308124_12734.cpp:20:14: error: 'b' was not declared in this scope
         sort(b, b+n, cmp);
              ^