java中nextInt用法

• 功能
• • 函数实现
  • • 三级目录

功能

给定一个参数n，nextInt(n)将返回一个大于等于0小于n的随机数，即：0 <= nextInt(n) < n。

函数实现

    /**
     * Returns a pseudo-random uniformly distributed {@code int}
     * in the half-open range [0, n).
     */
    public int nextInt(int n) {
        if (n <= 0) {
            throw new IllegalArgumentException("n <= 0: " + n);
        }
        if ((n & -n) == n) {
            return (int) ((n * (long) next(31)) >> 31);
        }
        int bits, val;
        do {
            bits = next(31);
            val = bits % n;
        } while (bits - val + (n - 1) < 0);
        return val;
    }
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三级目录