求0~7所能组成的奇数个数。
分析:组成1位数是4个,组成2位数是7*4个,组成3位数是7*8*4个,组成4位数是7*8*8*4个……
public class Example44 {
public static void main(String[] args) {
f();
}
public static void f() {
int sum = 4;
int j;
System.out.println("组成1位数是 " + sum + " 个");
sum = sum * 7;
System.out.println("组成2位数是 " + sum + " 个");
for (j = 3; j <= 9; j++) {
sum = sum * 8;
System.out.println("组成" + j + "位数是 " + sum + " 个");
}
}
}