View Compilation Error

0_0_25457770_31848.cpp: In function 'int main()':
0_0_25457770_31848.cpp:44:13: error: 'i' was not declared in this scope
         for(i=1;i<=n;i++)
             ^
0_0_25457770_31848.cpp:46:26: error: 'a' was not declared in this scope
             if(i != 1 && a[i].val != a[i-1].val)
                          ^
0_0_25457770_31848.cpp:48:15: error: 'a' was not declared in this scope
             b[a[i].pos] = cnt;
               ^