Java Classic Programming question 50-way 44

An odd number of 0~7 that can be composed.
Analysis: The composition of 1 digits is 4, composed of 2 digits is 7*4, the composition of 3 digits is 7*8*4, composed of 4 digits is 7*8*8*4 ...

public class Example44 {
public static void Main (string[] args) {
f ();
}

public static void F () {
int sum = 4;
Int J;
System.out.println ("composed of 1 digits is" + sum + "one");
sum = sum * 7;
System.out.println ("composed of 2 digits is" + sum + "one");
for (j = 3; J <= 9; j + +) {
sum = sum * 8;
System.out.println ("composition" + j + "Number of digits is" + sum + "x");
}
}
}

Java Classic Programming question 50-way 44