View Compilation Error

0_0_36331675_1721.cpp: In function 'int main()':
0_0_36331675_1721.cpp:41:20: error: 'sum' was not declared in this scope
         rep(i,1,n) sum+=a[i];
                    ^
0_0_36331675_1721.cpp:42:12: error: 'sum' was not declared in this scope
         if(sum<=w)
            ^
0_0_36331675_1721.cpp:42:17: error: 'w' was not declared in this scope
         if(sum<=w)
                 ^