[英]Program won't output the lowest number [Java]
我正在创建一个程序,用户在其中输入随机数,并返回最高和最低数。 我将highestNumber和lowestNumber初始化为数组中的第一个元素。 然后,我检查该数字是否大于或小于为各个变量分配的值。 除了将索引值与最小数字进行比较的if语句外,其他所有方法都起作用。 我不确定为什么它不起作用。 它与最高数字的if语句相反(顺便说一句)。 程序始终为最小数字返回0.0。 这是我的主要方法:
private static String arrayLimit;
private static double highestNumber;
private static double lowestNumber;
public static void main(String[] argument) throws IOException
{
BufferedReader console =
new BufferedReader(new InputStreamReader(System.in));
System.out.print("How many numbers do you want to enter? ");
arrayLimit = console.readLine();
int limit = Integer.parseInt (arrayLimit);
int[] number = new int[limit];
highestNumber = number[0];
lowestNumber = number[0];
for (int index = 0; index < limit; index++)
{
System.out.print("Number " + (index + 1) + ": ");
String input = console.readLine();
number[index] = Integer.parseInt(input);
if (number[index] > highestNumber)
{
highestNumber = number[index];
}
if (number[index] < lowestNumber)
{
lowestNumber = number[index];
}
}
System.out.println("Highest number: " + highestNumber);
System.out.println("Lowest number: " + lowestNumber);
}
请注意如何将最高和最低初始化为number[0]
。 此时,它们都为0。当您浏览数字列表时,没有任何事物会低于0(假设您仅输入正数),因此0将是您的输出。 我建议改为将其初始化为Integer.MAX_VALUE
根据定义,每个int都比该值低。 同样,您可能希望将highestNumber = number[0]
更改为highestNumber = Integer.MIN_VALUE
该值不小于任何值,这将使您的程序也可以处理负数。
我将
highestNumber
和lowestNumber
初始化为数组中的第一个元素。
不,您没有将这些变量初始化为数组的第一个元素:完成此操作后,程序可以正常运行。 问题是,您已经在number[0]
元素获得其第一个有意义的值之前进行了分配,而是存储了默认值。 这就是为什么您的程序产生最低数字为零的原因。
您可以通过存储最高和最低数字的索引来解决此问题,而不是存储数字本身:
highestIndex = 0;
lowestIndex = 0;
for (int index = 0; index < limit; index++)
{
System.out.print("Number " + (index + 1) + ": ");
String input = console.readLine();
number[index] = Integer.parseInt(input);
if (number[index] > number[highestIndex])
{
highestIndex = index;
}
if (number[index] < number[lowestIndex])
{
lowestIndex = index;
}
}
System.out.println("Highest number: " + number[highestIndex]);
System.out.println("Lowest number: " + number[lowestIndex]);
for (int index = 0; index < limit; index++) {
System.out.print("Number " + (index + 1) + ": ");
String input = console.readLine();
number[index] = Integer.parseInt(input);
if(index == 0){ // here you initialize highestNumber & lowestNumber
highestNumber = number[0];
lowestNumber = number[0];
}
if (number[index] > highestNumber)
{
highestNumber = number[index];
}
if (number[index] < lowestNumber)
{
lowestNumber = number[index];
}
}
**请注意,除了在用户实际输入number [0]的值之前通过number [0]初始化maximumNumber和lowestNumber之外,您的所有代码都很好,因此请在用户为number [0]输入值的循环中使用这些初始化语句当index = 0时。 就是这样。因为我在PC上进行了测试,所以可以尝试一下。
我将向您展示如何建议构建此代码。 我的主要观点是,您应该使用数组来构造代码,但是由于您使用的是面向对象的语言,因此我将使其更加面向对象。 我对Java不太了解,因此请考虑以下内容为伪代码。 某些类型可能是错误的,某些方法名称可能是组成的,等等。
class IntList {
private final int[] numbers;
private Integer highestNumber;
private Integer lowestNumber;
public IntList(int [] numbers, boolean makeCopy)
{
highestNumber = null;
lowestNumber = null;
if(makeCopy)
this.numbers = Arrays.copyOf(numbers, numbers.length);
else
this.numbers = numbers;
}
public static IntList getInput(BufferedReader reader, BufferedWriter writer)
{
writer.print("How many numbers do you want to enter? ");
String arrayLimit = reader.readLine();
int limit = Integer.parseInt (arrayLimit);
int[] numbers = new int[limit];
//Actually read in the numbers, using the reader and writer that were
//passed in, rather than reaching out to System.
return new IntList(numbers, false);
}
public int getHighest()
{
if(highestNumber!=null)
return highestNumber;
else
;//Find the highest number; set highestNumber to that value, then return that result.
}
public int getLowest()
{
//same idea here.
}
}
public class Main {
public static void main(String[] argument) throws IOException
{
//try-with-resources ensures that the reader gets closed properly. Since nothing
//else happens in the program, this doesn't matter so much, but it's generally a good
//habit to get into.
try(BufferedReader console =
new BufferedReader(new InputStreamReader(System.in)))
{
IntList list = IntList.getInput(console, System.out);
System.out.println("Highest number: " + list.getHighest());
System.out.println("Lowest number: " + list.getLowest);
}
}
}
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