注意：希望将其移至Code Review，并使用更清晰的答案结构和修改后的代码，这与除了calcmin方法之外的答案非常相似。
我正在尝试将这些代码分解为多种方法，并且我在第一位获得了成功，但其他两种方法似乎无法弄明白。
使用第二种方法，我试图做到这一点，它会询问用户一个整数，并不断提示它们，直到输入一个正确的整数。
使用第三种方法，我试图使它需要三个整数参数并返回这些参数的最小值。
我真的很感激这方面的帮助。我查看了我的书中的例子，似乎无法得到它。
我的代码：
import java.util.Scanner;
public class MinOfThreeInts
{
public static void intro ()
{
System.out.println("This program determines the minimum of three ints");
System.out.println("It gracefully reports errors when erroneous data is entered ");
System.out.println("For example, if you type in 'abc' when this program asked for an int");
System.out.println("the program will report the error & ask for another int");
System.out.println("Try giving it bad input ! \n\n");
}
public static void readInt (int value1, int value2, int value3)
{
System.out.print(" Please enter an integer value ");
Scanner console = new Scanner(System.in);
String input = console.nextLine();
Boolean goodInt;
int parsedValue = 0;
goodInt = false;
while (!goodInt)
{
try
{
parsedValue = Integer.parseInt(input);
goodInt = true;
}
catch(NumberFormatException ex)
{
System.out.print(" Invalid input, please enter Int ");
input = console.nextLine();
}
}
value1 = parsedValue;
// Get the second integer
System.out.print(" Please enter an integer value ");
input = console.nextLine();
goodInt = false;
while (!goodInt)
{
try
{
parsedValue = Integer.parseInt(input);
goodInt = true;
}
catch(NumberFormatException ex)
{
System.out.print(" Invalid input, please enter Int ");
input = console.nextLine();
}
}
value2 = parsedValue;
// Get the third integer
System.out.print(" Please enter an integer value ");
input = console.nextLine();
goodInt = false;
while (!goodInt)
{
try
{
parsedValue = Integer.parseInt(input);
goodInt = true;
}
catch(NumberFormatException ex)
{
System.out.print(" Invalid input, please enter Int ");
input = console.nextLine();
}
}
value3 = parsedValue;
}
public static void calcMin (min)
{
int min = value1;
if (value2 < min)
{
min = value2;
}
if (value3 < min)
{
min = value3;
}
// Now report the results
System.out.println(" The minimum value of the three ints is " + min);
}
public static void main(String[] args)
{
value1 = readInt(console);
value2 = readInt(console);
value3 = readInt(console);
min = calcMin(value1,value2,value3);
}
}
答案 0 :(得分：2)
你有几个问题。我重构了您的代码并添加了评论，我保持接近您的代码，以便为您提供有关可以改进的地方的见解。
首先，代码：
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
public class MinOfThreeInts {
//the main method, things start here
public static void main(String[] args) {
//initialize a new scanner that the application will use
Scanner console = new Scanner(System.in);
//print the intro
intro();
//read the values one by one and save them in a variable
int value1 = readInt(console);
int value2 = readInt(console);
int value3 = readInt(console);
//calculate the minimum and save it in the min variable
int min = calcMin(Arrays.asList(value1,value2,value3));
// Now report the results
System.out.println(" The minimum value of the three ints is " + min);
}
/**
* Reads an integer from the given console
*/
public static int readInt(Scanner console) {
System.out.print(" Please enter an integer value ");
//read the input
int parsedValue = 0;
boolean goodInt = false;
//as long as we don't find a valid number
while (!goodInt)
{
try
{
//read the input
String input = console.nextLine();
//try to parse the value
parsedValue = Integer.parseInt(input);
//set goodInt to true so that the while loop will end
goodInt = true;
}
catch(NumberFormatException ex)
{
//if the provivded value was not an integer, print a message and return to the start of the while loop
System.out.print(" Invalid input, please enter Int ");
}
}
return parsedValue;
}
/**
* calculates the minimum of a list of values
*/
public static int calcMin (List<Integer> values) {
//find the minimum and return the value
return Collections.min(values);
}
/**
* prints an intro message
*/
public static void intro () {
System.out.println("This program determines the minimum of three ints");
System.out.println("It gracefully reports errors when erroneous data is entered ");
System.out.println("For example, if you type in 'abc' when this program asked for an int");
System.out.println("the program will report the error & ask for another int");
System.out.println("Try giving it bad input ! \n\n");
}
}
现在，您可以采取哪些措施来改进：
编译代码无法编译，请始终注意您的代码编译，然后稍微编辑它，直到再次编译
范围你的代码有多个声明的整数，问题是这些值在其他方法中是不可见的，如果你声明一个变量，在某些方法中说int value1，另一个方法将无法看到它。如果在另一个方法中有另一个int value1，它只会在该特定方法中可见，它实际上是另一个变量
参数与返回类型方法获取参数，返回某些内容。参数是方法的输入，返回的值是方法的结果。以您的方法为例：public static void readInt (int value1, int value2, int value3)。这是一个应该从控制台读取整数值的方法。但是，此方法签名表示它需要3个整数作为参数。这些整数将按值传递，因为它们是基本类型，因此您无法传递它们，然后填充它们然后返回它们。也没有返回类型，因此该方法不返回某些内容。由于整数参数value1，value2和value3仅在方法范围内可见，因此您将丢失数据。与新签名进行比较：public static int readInt(Scanner console)。此方法使控制台从作为参数读取并返回一个整数，即已读取的数字。此方法封装了重试。