基本上我有代码允许用户创建一个数组，但由于某种原因，值保持在0.0
以下是代码：
/**
* @author Brian
* @version 21 Oct 2017
*/
/**
* Example of program execution:
* Using arrays, and finding the average, max and sum.
* The array with 4 elements is [4.5, 2.0, 1.2, 3.3]
* The sum of [4.5, 2.0, 1.2, 3.3] is 11.00
* The Average of [4.5, 2.0, 1.2, 3.3] is 2.75
* The minimum of [4.5, 2.0, 1.2, 3.3] is 1.20
* How many numbers: 3
* Enter lower and upper range limits: 1 100
* Enter number 0: 2
* Enter number 1: 2
* Enter number 2: 2
* The sum of [0.0, 0.0, 0.0] is 0.00
* The Average of [0.0, 0.0, 0.0] is 0.00
* The minimum of [0.0, 0.0, 0.0] is 0.00
* After fill with 1.2, the array is [1.2, 1.2, 1.2, 1.2, 1.2, 1.2]
*/
import java.util.Scanner;
public class EngArray {
/**
* Test the array methods
* @param args the command line arguments
*/
public static void main(String[] args) {
System.out.println("Using arrays, and finding the average, max and sum.");
// a) Declare and initialise an array to hold the real data values 2.3, 4.6, 3.0 and 1.1.
double[] array1 = {
4.5,
2.0,
1.2,
3.3
};
// b) Using the provided toString( ) method display the array values
// Example code to test method toString( ) below, replace test array with the above array name.
String array1Str = toString(array1);
System.out.println("The array with 4 elements is " + array1Str);
// c) Invoke calcSum and display the numbers and the sum
System.out.printf("The sum of %s is %.2f ", array1Str, calcSum(array1));
// d) Invoke calcAvg and display the numbers and their average
System.out.printf("\nThe Average of %s is %.2f ", array1Str, calcAvg(array1));
// e) Invoke findMin and display the minimum
System.out.printf("\nThe minimum of %s is %.2f ", array1Str, findMin(array1));
// g) Invoke makeArray and then display the sum, average and minimum of new array
double[] madeArray = makeArray();
String madeArrayStr = toString(madeArray);
System.out.printf("The sum of %s is %.2f ", madeArrayStr, calcSum(madeArray));
System.out.printf(" \nThe Average of %s is %.2f ", madeArrayStr, calcAvg(madeArray));
System.out.printf(" \nThe minimum of %s is %.2f ", madeArrayStr, findMin(madeArray));
// h) Invoke fill to set a new array of 6 elements to 1.2 and then display modified array
double[] arrayofsix = {
3.4,
5.1,
9.8,
2.2,
4.0,
7.6
};
fill(arrayofsix, 1.2);
String arrayofsixStr = toString(arrayofsix);
System.out.printf(" \nAfter fill with %s, the array is %s ", "1.2", arrayofsixStr);
}
public static double calcSum(double[] array) {
double[] array1;
double sum = 0;
for (int counter = 0; counter < array.length; counter++)
sum += array[counter];
return sum;
}
public static double calcAvg(double[] array) {
double Avg = 0;
double sum = 0;
for (int counter = 0; counter < array.length; counter++)
sum += array[counter];
Avg = sum / array.length;
return Avg;
}
public static double findMin(double[] array) {
double Min = array[0];
for (int i = 1; i < array.length; i++) {
if (array[i] < Min) {
Min = array[i];
}
}
return Min;
}
/**
* Returns a string representation of the array i.e. a comma separated list
* of elements within [ ]. Similar to java.util.Arrays.toString(double[] a) method.
* Each array element will be displayed by String.valueOf(double).
* @param array the array whose string representation is required
* @return a string representation of array
*/
public static String toString(double[] array) {
String arrayStr = "[";
for (int i = 0; i < array.length; i++) {
if (i > 0) // Insert comma separator after first one
arrayStr += ", ";
arrayStr += String.valueOf(array[i]);
}
arrayStr += "]";
return arrayStr;
}
/**
* Input a set of elements and store in the created array. The user specifies
* the size of the array, and enters the elements.
* @return the created array
*/
public static double[] makeArray() // Part f)
{
final String format = "%.2f";
Scanner input = new Scanner(System.in);
System.out.print("\nHow many numbers: ");
int numNumbers = input.nextInt();
System.out.print("Enter lower and upper range limits: ");
double lower = input.nextDouble();
double upper = input.nextDouble();
double[] numArray = new double[numNumbers];
for (int i = 0; i < numNumbers; i++) {
double number;
System.out.printf("Enter number %d: ", i);
number = input.nextDouble();
while (number < lower || number > upper) {
System.out.print("Please re-enter in range ");
System.out.printf("[" + format + " to " + format + "]: ", lower, upper);
number = input.nextDouble();
}
}
return numArray;
}
/**
* initialise each element of the array to the given value.
*/
public static void fill(double[] array, double value) {
double[] array6 = new double[6];
for (int i = 0; i < array.length; i++)
array[i] = value;
}
}
我有一种感觉，影响这一点的代码的唯一部分就在这里：
public static double[] makeArray() // Part f)
{
final String format = "%.2f";
Scanner input = new Scanner(System.in);
System.out.print("\nHow many numbers: ");
int numNumbers = input.nextInt();
System.out.print("Enter lower and upper range limits: ");
double lower = input.nextDouble();
double upper = input.nextDouble();
double[] numArray = new double[numNumbers];
for (int i = 0; i < numNumbers; i++) {
double number;
System.out.printf("Enter number %d: ", i);
number = input.nextDouble();
while (number < lower || number > upper) {
System.out.print("Please re-enter in range ");
System.out.printf("[" + format + " to " + format + "]: ", lower, upper);
number = input.nextDouble();
}
}
return numArray;
}
答案 0 :(得分：-1)
public static double[] makeArray() // Part f)
{
final String format = "%.2f";
Scanner input = new Scanner(System.in);
System.out.print("\nHow many numbers: ");
int numNumbers = input.nextInt();
System.out.print("Enter lower and upper range limits: ");
double lower = input.nextDouble();
double upper = input.nextDouble();
double[] numArray = new double[numNumbers];
for (int i = 0; i < numNumbers; i++) {
double number;
System.out.printf("Enter number %d: ", i);
number = input.nextDouble();
while (number < lower || number > upper) {
System.out.print("Please re-enter in range ");
System.out.printf("[" + format + " to " + format + "]: ", lower, upper);
number = input.nextDouble();
}
// YOU FORGOT TO ASSIGN THE GENERATED NUMBER TO ARRAY
numArray[i] = number;
}
return numArray;
}