实现固定小数位数值

最新推荐文章于 2023-04-19 00:16:46 发布

原创最新推荐文章于 2023-04-19 00:16:46 发布 · 348 阅读

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本文介绍了一个使用C++模板元编程实现的固定精度算术类库，该类库能够提供比浮点数更精确的数值计算，并且通过模板参数指定精度。文中提供了完整的类定义和一个简单的示例程序，演示了如何使用这个类来累积一系列相同的小数值。

#include <iostream>

using namespace std;

template<int E>
struct BasicFixedReal
{
    typedef BasicFixedReal self;
    static const int factor = 1 << (E - 1);
    BasicFixedReal() : m(0) {}
    BasicFixedReal(double d) : m(static_cast<int>(d * factor)) {}
    self& operator+=(const self& x) { m += x.m; return *this; }
    self& operator-=(const self& x) { m -= x.m; return *this; }
    self& operator*=(const self& x) { m *= x.m; m >> E;  return *this; }
    self& operator/=(const self& x) { m /= x.m; m *= factor; return *this; }
    self& operator*=(int x) { m *= x; return *this; }
    self& operator/=(int x) { m /= x; return *this; }
    self& operator-() { return self(-m); }
    double toDouble() const { return double(m) / factor; }
    friend self operator+(self x, const self& y) { return x += y; }
    friend self operator-(self x, const self& y) { return x -= y; }
    friend self operator*(self x, const self& y) { return x *= y; }
    friend self operator/(self x, const self& y) { return x /= y; }
    friend bool operator==(const self& x, const self& y) { return x.m == y.m; }
    friend bool operator!=(const self& x, const self& y) { return x.m != y.m; }
    friend bool operator<(const self& x, const self& y) { return x.m < y.m; }
    friend bool operator>(const self& x, const self& y) { return x.m > y.m; }
    friend bool operator>=(const self& x, const self& y) { return x.m >= y.m; }
    friend bool operator<=(const self& x, const self& y) { return x.m <= y.m; }
private:
    int m;
};

typedef BasicFixedReal<10> FixedReal;

int main(int argc, char** argv)
{
    FixedReal x(0);
    for (int i = 0; i < 100; ++i) { x += FixedReal(0.0625);
    }
    cout << x.toDouble() << endl;
    system("pause");
     return 0;
}