View Compilation Error

1000593_0_0_5191.cpp: In function `int main()':
1000593_0_0_5191.cpp:73: error: no match for 'operator=' in 'num[i] = (&((((BigNum*)(&num)) + ((BigNum*)(((unsigned int)i) * 400u))) - 400u)->BigNum::operator+(((BigNum&)((((BigNum*)(&num)) + ((BigNum*)(((unsigned int)i) * 400u))) - 800u))))->BigNum::operator+(((BigNum&)((((BigNum*)(&num)) + ((BigNum*)(((unsigned int)i) * 400u))) - 1600u)))'
1000593_0_0_5191.cpp:30: note: candidates are: void BigNum::operator=(BigNum&)