我正在尝试使用种子值打印有限数量的tribonacci序列（其中任何一项的值等于前三个项的和，即[2,3,5,10,18,33 ...]）从用户输入中获得。使用0和1以外的任何其他正值，该代码将始终有效，如下所示：
2
3
5
Printing...
[2, 3, 5, 10, 18, 33, 61, 112, 206, 379, 697, 1282, 2358, 4337, 7977, 14672, 26986, 49635, 91293, 167914]
Process finished with exit code 0
但是以0、1和1作为种子，我得到：
0
1
1
Printing...
[0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Process finished with exit code 0
这是代码（我知道过分明确的注释，这是有原因的）：
import java.util.Arrays;
import java.util.Scanner;
public class Tribonacci {
public static void main(String[] args) throws InterruptedException {
System.out.printf("Hello!\n");
Thread.sleep(2000);
System.out.printf("The purpose of this program is to display the first twenty terms of either a Fibonacci sequence or a Tribonacci sequence\n");
System.out.printf("To start, type \"F\" for Fibonacci or \"T\" for Tribonacci:\n");//Give prompt options
Scanner seqeuence = new Scanner(System.in);
String typeseq = seqeuence.next();//get user input, based on ^ prompt ^
printSequence(typeseq);
}
private static void printSequence(String typeOfSequence) throws InterruptedException {
//checks for which kind of sequence they want to print based on above prompt
switch (typeOfSequence) {
case "T"://if user types "T"
System.out.printf("You have chosen to print the first twenty terms of the Tribonacci sequence\n");
Thread.sleep(2000);
System.out.printf("We will need the seed terms for this to work, so input THREE non-negative integers, in numerical order:\n");
Scanner getTrib = new Scanner(System.in);
int[] tSeeds = new int[3];//scans for three seeds from the user, stores in an array of size 3
//put each seed term into an array, in order to perform arithmetic on the elements later
for (int i = 0; i < tSeeds.length; i++) {
tSeeds[i] = getTrib.nextInt();
}
int[] newTSeq = new int[20];//final array to be printed
newTSeq[0] = tSeeds[0];
newTSeq[1] = tSeeds[1];
newTSeq[2] = tSeeds[2];
int incrementT = 0;//used to traverse the array and move which seeds should be summed
for (int itemT : newTSeq) {
if (itemT == tSeeds[0] || itemT == tSeeds[1] || itemT == tSeeds[2]) {
continue;
} else {
newTSeq[3 + incrementT] = newTSeq[incrementT] + newTSeq[incrementT + 1] + newTSeq[incrementT + 2];
++ incrementT;
}
}
System.out.printf("Printing...\n");
Thread.sleep(2000);
System.out.print(Arrays.toString(newTSeq));//terms are converted into strings to be printed
break;
case "F"://if user types "F"
System.out.printf("You have chosen to print the first twenty terms of the Fibonacci sequence\n");
Thread.sleep(2000);
System.out.printf("We will need the seed terms for this to work, so input TWO non-negative integers, in numerical order:\n");
Scanner getFib = new Scanner(System.in);
int[] fSeeds = new int[2];//scan user input of TWO integers into an array that holds TWO integers
//put each seed term into array for later computation, like above
for (int i = 0; i < fSeeds.length; i++) {
fSeeds[i] = getFib.nextInt();
}
int[] newFSeq = new int[20];//final array to be printed
newFSeq[0] = fSeeds[0];
newFSeq[1] = fSeeds[1];
int incrementF = 0;
for (int itemF : newFSeq) {
if (itemF == newFSeq[0] || itemF == newFSeq[1]) { //if the iterator is on one of the seeds, don't sum
continue;
} else {
newFSeq[2 + incrementF] = newFSeq[incrementF] + newFSeq[incrementF + 1];//sums the two preceding terms
incrementF++;
}
}
System.out.printf("Printing...\n");
Thread.sleep(2000);
System.out.print(Arrays.toString(newFSeq));//convert all array values to strings, to be printed
break;
default://if neither case is satisfied, print this message
System.out.printf("Restart the program. Next time, input the SUGGESTED prompt items \"F\" for Fibonacci or \"T\" for Tribonacci");
}
}
}
最佳答案
好吧，你有这种奇怪的情况
if (itemT == tSeeds[0] || itemT == tSeeds[1] || itemT == tSeeds[2]) {
continue;
}
这意味着如果
newTSeq，tSeeds[0]或tSeeds[1]中的任何一个为0（由于默认情况下tSeeds[2]的所有元素的itemT为0，则不分配任何内容给newTSeq数组，如果输入为0,1,1，则只能在循环前将newTSeq[1]和newTSeq[2]更改为1。我不确定这种情况应该做什么。您可能可以将其删除。