動手動腦一：純隨機數發生器

package first;
/*
 * 純隨機數發生器
 * 生成1000個隨機整數
 */
public class TestRandom {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        long seed = System.currentTimeMillis();// 種子
        int i;
        int count = 0;
        // Modulus=231-1=int.MaxValue
        // Multiplier=75=16807
        long random = (16807 * seed) % Integer.MAX_VALUE;
        for (i = 1; i <= 1000; i++) {
            random = (16807 * random) % Integer.MAX_VALUE;
            System.out.print(random + " ");
            count++;
            if (count % 5 == 0)
                System.out.println();
        }
    }
}

運行截圖

查看JDK中System.out.println()方法的部分內容

 /**
     * Prints an integer and then terminate the line.  This method behaves as
     * though it invokes <code>{@link #print(int)}</code> and then
     * <code>{@link #println()}</code>.
     *
     * @param x  The <code>int</code> to be printed.
     */
    public void println(int x) {
        synchronized (this) {
            print(x);
            newLine();
        }
    }
   /**
     * Prints a String and then terminate the line.  This method behaves as
     * though it invokes <code>{@link #print(String)}</code> and then
     * <code>{@link #println()}</code>.
     *
     * @param x  The <code>String</code> to be printed.
     */
    public void println(String x) {
        synchronized (this) {
            print(x);
            newLine();
        }
    }

第四周動手動腦