View Compilation Error

0_0_25481487_24421.cpp: In function 'int main()':
0_0_25481487_24421.cpp:52:16: error: 'ar' was not declared in this scope
    scanf("%d",&ar[i]);
                ^
0_0_25481487_24421.cpp:54:6: error: 'ar' was not declared in this scope
   MS(ar,0,n-1);
      ^