class subtractive_rng : public unary_function<unsigned int, unsigned int> {
private:
unsigned int _M_table[55];
size_t _M_index1;
size_t _M_index2;
public:
unsigned int operator()(unsigned int __limit) {
_M_index1 = (_M_index1 + 1) % 55;
_M_index2 = (_M_index2 + 1) % 55;
_M_table[_M_index1] = _M_table[_M_index1] - _M_table[_M_index2];
return _M_table[_M_index1] % __limit;
}
void _M_initialize(unsigned int __seed)
{
unsigned int __k = 1;
_M_table[54] = __seed;
size_t __i;
for (__i = 0; __i < 54; __i++) {
size_t __ii = (21 * (__i + 1) % 55) - 1;
_M_table[__ii] = __k;
__k = __seed - __k;
__seed = _M_table[__ii];
}
for (int __loop = 0; __loop < 4; __loop++) {
for (__i = 0; __i < 55; __i++)
_M_table[__i] = _M_table[__i] - _M_table[(1 + __i + 30) % 55];
}
_M_index1 = 0;
_M_index2 = 31;
}
subtractive_rng(unsigned int __seed) { _M_initialize(__seed); }
subtractive_rng() { _M_initialize(161803398u); }
};
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