1.排序
1.1.实例
@Test
public void tests() {
int[] numbers = { 3, 2, 20, 54, 10, 5, 78, 1, 100 };
int tmep = 0;
for (int i = 0; i < numbers.length; i++) {
for (int j = 0; j < numbers.length - i - 1; j++)
if (numbers[j] > numbers[j + 1]) {
tmep = numbers[j];
numbers[j] = numbers[j + 1];
numbers[j + 1] = tmep;
}
}
for (int n = 0; n < numbers.length; n++) {
System.out.print(numbers[n] + ",");
}
System.out.println("===============");
for (int m = numbers.length - 1; m >= 0; m--) {
System.out.print(numbers[m] + ";");
}
System.out.println("list结果：===============");
List<Integer> list = new ArrayList<Integer>();
for (int a = 0; a < numbers.length; a++) {
list.add(numbers[a]);
}
Collections.sort(list);
for (Integer str : list) {
System.out.print(str + ";");
}
}
1.2.实例
public static void main(String[] arg){
Comparable []num={4,9,12,3,2,45,89};
insertionSort(num);
for(int i=0;i<num.length;i++){
System.out.print(num[i]+",");
}
}
public static void insertionSort(Comparable []data){
for(int index=1;index<data.length;index++){
Comparable key =data[index];
int position=index;
while(position>0 && data[position-1].compareTo(key)>0){
data[position]=data[position-1];
position--;
}
data[position]=key;
}
}
2.求素数
@Test
public void testNum() {
for (int m = 2; m < 100; m++) {
int n;
for (n = 2; n <= (int) (Math.sqrt(m)); n++) {
if (m % n == 0) {
break;
}
}
if (n > (int) (Math.sqrt(m))) {
System.out.print(m + ";");
}
}
System.out.println("==============");
for (int i = 2; i < 100; i++) {
int j;
for (j = 2; j <= i / 2; j++) {
if (i % j == 0) {
break;
}
}
if (j > i / 2) {
System.out.print(i + ";");
}
}
}