View Compilation Error

67841_0_14337.cpp: In constructor `BigNum::BigNum(const char*)':
67841_0_14337.cpp:48: error: `bitlen' undeclared (first use this function)
67841_0_14337.cpp:48: error: (Each undeclared identifier is reported only once for each function it appears in.)
67841_0_14337.cpp:49: error: assignment of read-only location
67841_0_14337.cpp:52: error: assignment of read-only location
67841_0_14337.cpp:53: error: assignment of read-only location
67841_0_14337.cpp:54: error: assignment of read-only location
67841_0_14337.cpp:56: error: invalid conversion from `const void*' to `void*'
67841_0_14337.cpp:56: error:   initializing argument 1 of `void* memset(void*, int, size_t)'