// 先聲明兩個全局變量
private static int length;
private static int count;
// 調用此方法,參數為可變長數組
private static void execute(String[]... args) {
length = args.length;
PrintcartesianProduct(args, "", 0);
System.out.println("共有" + count + "種組合方式");
}
// 遞歸調用列印笛卡爾積
private static void PrintcartesianProduct(String[][] args, String result, int index) {
if (index < length) {
if(args[index].length == 0){
PrintcartesianProduct(args, result + " ", index + 1);
}
for (String s : args[index]) {
PrintcartesianProduct(args, result + " " + s + " ", index + 1);
}
} else if(length != 0){
System.out.println(result);
count++;
}
}
// main方法調用,支援以下多種調用方式。
public static void main(String[] args) {
execute();
execute(new String[]{"A","B"});
execute(new String[]{"A","B"},new String[]{"C","D"});
execute(new String[]{"A","B"},new String[]{},new String[]{"C","D"});
}
運作結果如:
A C
A D
B C
B D
共有4種組合方式