将一个数分解为他的质因数的乘积形式。
import java.util.ArrayList;public class FenJie {static int n = 100;static void fenjie(int i,ArrayList sushu) {//非素数分解方法（递归）for(int j = 2;j<=n;j++) {if(sushu.contains(j))if(i%j == 0) {int s = i/j;if(sushu.contains(s)) {System.out.println( j + " * " + s);break;}else {System.out.print( j + " * ");fenjie(s,sushu);break;}}}}public static void main(String[] args) {ArrayList sushu = new ArrayList();sushu.add(2);for(int i = 3;i<=n;i++) {int j = 2;for(;j<=i/2;j++) {if(i%j == 0)break;}if(j > i/2)sushu.add(i);}for(int i = 2;i<=n;i++) {if(sushu.contains(i))//如果是素数，则直接输出1*这个数System.out.println(i + " = " + "1" + " * " + i);else {//否则进行分解System.out.print(i + " = ");fenjie(i,sushu);}}}}输出结果