View Compilation Error

0_0_4372930_12613.cpp: In function `std::ostream& operator<<(std::ostream&, const bign&)':
0_0_4372930_12613.cpp:71: error: 'const struct bign' has no member named 'str'
0_0_4372930_12613.cpp: In function `int main()':
0_0_4372930_12613.cpp:77: error: conversion from `int' to non-scalar type `bign' requested
0_0_4372930_12613.cpp:82: error: no match for 'operator+=' in 'f[(i * 2)] += (((bign*)(&f)) + (+(unsigned int)((i - j) * 1608)))->bign::operator*(((const bign&)((const bign*)((((bign*)(&f)) + ((bign*)(j * 1608))) - 1608u))))'