欧几里得算法实现

求最大公约数

int gcd(int m, int n) {
    int r, mid;
    if (m < n) {
        mid = m;
        m = n;
        n = mid;
    }
    while ((r = m%n) != 0) {
        m = n;
        n = r;
    }
    return n;
}

求最大公约数d，并求出am+bn=d中a和b

int gcd(int m, int n, int &a, int &b) {
    int a1, b1, mid, q, r;
    bool fGreater = (m >= n);
    if (!fGreater) {
        mid = m;
        m = n;
        n = mid;
    }
    a1 = b = 1;
    a = b1 = 0;
    while ((r = m%n) != 0) {
        q = m / n;
        //得到相应项数值
        m = n;
        n = r;
        mid = a1;
        a1 = a;
        a = mid - q*a;
        mid = b1;
        b1 = b;
        b = mid - q*b;
    }
    if (!fGreater) {
        mid = a;
        a = b;
        b = mid;
    }
    return n;
}

 所有代码均经过测试，结果正确。