如何生成一个简化分数的Java方法？

Question

我写了一个分数类，并与简化有困难。

当我创建分数对象时，一切都很好，我只是觉得我的逻辑由于简化而混乱。

（num和den分别是类中分子和分母的专用变量）

以下是我的GCD和Simplify方法：

/**
 * Returns the absolute value of the greatest common divisor of this
 * fraction's numerator and denominator. If the numerator or denominator is
 * zero, this method returns 0. This method always returns either a positive
 * integer, or zero.
 * 
 * @return Returns the greatest common denominator
 */
private int gcd() {
    int s;
    if (num > den)
        s = den;
    else
        s = num;
    for (int i = s; i > 0; i--) {
        if ((num % i == 0) && (den % i == 0))
            return i;
    }
    return -1;
}

/**
 * Changes this fraction's numerator and denominator to "lowest terms"
 * (sometimes referred to as a "common fraction"), by dividing the numerator
 * and denominator by their greatest common divisor. This includes fixing
 * the signs. For example, if a fraction is 24/-18, this method will change
 * it to -4/3. If the numerator or denominator of the fraction is zero, no
 * change is made.
 */
public void simplify() {

    if (isZero() == false) {// Making sure num or den is not zero.
        this.fixSigns(); // Fix signs first

        if (gcd() > 1) {
            this.num = num / gcd();
            this.den = num / gcd();
        }
    }
}

Answer 1

我马上看到两件事：对于分子和分母中的每一个，您将num除以gcd（）两次。此外，一旦更改分子，则调用gcd（）的结果可能会更改。调用“gcd”一次，存储其结果，稍后使用：

int gcd = gcd();
if (gcd > 1) {
   this.num = this.num / gcd;
   this.den = this.den / gcd;
}

此外，还有更有效的获取最大公约数的方法：维基百科页面。参见该页上的欧几里德算法。