View Compilation Error

0_0_13978148_24453.cpp: In function 'int main()':
0_0_13978148_24453.cpp:17:16: error: invalid use of non-lvalue array
             sum+=Month[i++];
                ^
0_0_13978148_24453.cpp:17:16: error:   in evaluation of 'operator+=(int, int [13])'