copyingarrays.java

来自「Thinking in JAVA第四版源代码」· Java 代码 · 共 43 行

//: arrays/CopyingArrays.java
// Using System.arraycopy()
import java.util.*;
import static net.mindview.util.Print.*;

public class CopyingArrays {
  public static void main(String[] args) {
    int[] i = new int[7];
    int[] j = new int[10];
    Arrays.fill(i, 47);
    Arrays.fill(j, 99);
    print("i = " + Arrays.toString(i));
    print("j = " + Arrays.toString(j));
    System.arraycopy(i, 0, j, 0, i.length);
    print("j = " + Arrays.toString(j));
    int[] k = new int[5];
    Arrays.fill(k, 103);
    System.arraycopy(i, 0, k, 0, k.length);
    print("k = " + Arrays.toString(k));
    Arrays.fill(k, 103);
    System.arraycopy(k, 0, i, 0, k.length);
    print("i = " + Arrays.toString(i));
    // Objects:
    Integer[] u = new Integer[10];
    Integer[] v = new Integer[5];
    Arrays.fill(u, new Integer(47));
    Arrays.fill(v, new Integer(99));
    print("u = " + Arrays.toString(u));
    print("v = " + Arrays.toString(v));
    System.arraycopy(v, 0, u, u.length/2, v.length);
    print("u = " + Arrays.toString(u));
  }
} /* Output:
i = [47, 47, 47, 47, 47, 47, 47]
j = [99, 99, 99, 99, 99, 99, 99, 99, 99, 99]
j = [47, 47, 47, 47, 47, 47, 47, 99, 99, 99]
k = [47, 47, 47, 47, 47]
i = [103, 103, 103, 103, 103, 47, 47]
u = [47, 47, 47, 47, 47, 47, 47, 47, 47, 47]
v = [99, 99, 99, 99, 99]
u = [47, 47, 47, 47, 47, 99, 99, 99, 99, 99]
*///:~