View Compilation Error

0_0_33928058_1844.cpp:19:12: error: expected initializer before 'long'
 #define ll long long
            ^
0_0_33928058_1844.cpp:31:1: note: in expansion of macro 'll'
 ll ret; 
 ^
0_0_33928058_1844.cpp: In function 'void merge(int*, int, int, int)':
0_0_33928058_1844.cpp:42:4: error: 'ret' was not declared in this scope
    ret += (mid-i+1);
    ^
0_0_33928058_1844.cpp: In function 'int main()':
0_0_33928058_1844.cpp:76:11: error: 'a' was not declared in this scope
    cin >> a[i];
           ^
0_0_33928058_1844.cpp:77:3: error: 'ret' was not declared in this scope
   ret = 0;
   ^
0_0_33928058_1844.cpp:78:9: error: 'a' was not declared in this scope
   msort(a, 0, n-1);
         ^