Java 实例 - 数组添加元素
Java数组添加元素,insertElement () 方法向数组插入元素
MainClass.java 文件
import java.util.Arrays;
public class MainClass {
public static void main(String args[]) throws Exception {
int array[] = { 2, 5, -2, 6, -3, 8, 0, -7, -9, 4 };
Arrays.sort(array);
printArray("数组排序", array);
int index = Arrays.binarySearch(array, 1);
System.out.println("元素 1 所在位置(负数为不存在):" + index);
int newIndex = -index - 1;
array = insertElement(array, 1, newIndex);
printArray("数组添加元素 1", array);
}
private static void printArray(String message, int array[]) {
System.out.println(message + ": [length: " + array.length + "]");
for (int i = 0; i < array.length; i++) {
if (i != 0){
System.out.print(", ");
}
System.out.print(array[i]);
}
System.out.println();
}
private static int[] insertElement(int original[], int element, int index) {
int length = original.length;
int destination[] = new int[length + 1];
System.arraycopy(original, 0, destination, 0, index);
destination[index] = element;
System.arraycopy(original, index, destination, index + 1, length - index);
return destination;
}
}
public class MainClass {
public static void main(String args[]) throws Exception {
int array[] = { 2, 5, -2, 6, -3, 8, 0, -7, -9, 4 };
Arrays.sort(array);
printArray("数组排序", array);
int index = Arrays.binarySearch(array, 1);
System.out.println("元素 1 所在位置(负数为不存在):" + index);
int newIndex = -index - 1;
array = insertElement(array, 1, newIndex);
printArray("数组添加元素 1", array);
}
private static void printArray(String message, int array[]) {
System.out.println(message + ": [length: " + array.length + "]");
for (int i = 0; i < array.length; i++) {
if (i != 0){
System.out.print(", ");
}
System.out.print(array[i]);
}
System.out.println();
}
private static int[] insertElement(int original[], int element, int index) {
int length = original.length;
int destination[] = new int[length + 1];
System.arraycopy(original, 0, destination, 0, index);
destination[index] = element;
System.arraycopy(original, index, destination, index + 1, length - index);
return destination;
}
}
以上代码运行输出结果为:
数组排序: [length: 10] -9, -7, -3, -2, 0, 2, 4, 5, 6, 8 元素 1 所在位置(负数为不存在):-6 数组添加元素 1: [length: 11] -9, -7, -3, -2, 0, 1, 2, 4, 5, 6, 8
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