Question

我是一名新的程序员，如果这个问题有点基础，请原谅我。

该程序的目标是对“最佳体重”进行简单计算，并在运行期间通过第35行中的a和b字符串比较不断抛出异常。我试图删除逻辑运算符，但似乎仍然没有是问题。我哪里错了？

import java.util.*;

public class WeightCalc {

  //Initialize variables
  static int feet = 0, inches = 0, totalWeight = 0;
  static boolean isMale;

  public static void optimalWeight(){
    // Calculate optimal weight
    if (isMale == true){
      if (feet >= 5){
        totalWeight = 106 + 6*(inches);
      } else{
        System.out.print("Error, you're a midget.");
      }
    }
    if (isMale == false){  
      if (feet >= 5){
        totalWeight = 100 + 5*(inches);
      } else{
        System.out.print("Error, you're a midget.");
      }
    }
  }

  public static void main(String[] args){

    String a = "Male", b = "male";

    // Initialize kboard Scanner
    Scanner kboard = new Scanner(System.in);

    // Ask for gender and assign isMale
    System.out.println("What is your gender? ");
    String gender = kboard.nextLine();
    if (gender.equals(a) || gender.equals(b)){
      isMale = true;
    }else {
      isMale = false;
    }

    // Ask for height, first feet, then inches
    System.out.println("What is your height in regards to feet? ");
    kboard.nextInt(feet);
    System.out.println("What is your remaining h eight in inches? ");
    kboard.nextInt(inches);

    //Call optimalWeight method and run
    optimalWeight();

    // Print the output
    System.out.println("Your optimal weight should be " + totalWeight + ".");

    // Set isMale opposite to what it was before and calculate opposite sex's potential weight
    isMale = !isMale;
    optimalWeight();

    // Print the output of the second run
    System.out.println("If you were of the opposite sex, your weight would be " + totalWeight + ".");

    // Close the Scanner variable
    kboard.close();
  }
}

Answer 1

这一行：

kboard.nextInt(feet);

应该是

feet = kboard.nextInt();

当您向Scanner.nextInt提供int参数时，它被视为您要输入的数字的基数。 feet的值为零，您实际上没有基数零数，因此错误。

请注意错误doesn't occur on the line you claim：

Exception in thread "main" java.util.regex.PatternSyntaxException: Unclosed character class near index 525
(([-+]?(((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))))|(((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))|(\Q-\E((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             ^
    at java.util.regex.Pattern.error(Pattern.java:1955)
    at java.util.regex.Pattern.clazz(Pattern.java:2548)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.clazz(Pattern.java:2504)
    at java.util.regex.Pattern.sequence(Pattern.java:2063)
    at java.util.regex.Pattern.expr(Pattern.java:1996)
    at java.util.regex.Pattern.group0(Pattern.java:2905)
    at java.util.regex.Pattern.sequence(Pattern.java:2051)
    at java.util.regex.Pattern.expr(Pattern.java:1996)
    at java.util.regex.Pattern.group0(Pattern.java:2905)
    at java.util.regex.Pattern.sequence(Pattern.java:2051)
    at java.util.regex.Pattern.expr(Pattern.java:1996)
    at java.util.regex.Pattern.group0(Pattern.java:2905)
    at java.util.regex.Pattern.sequence(Pattern.java:2051)
    at java.util.regex.Pattern.expr(Pattern.java:1996)
    at java.util.regex.Pattern.group0(Pattern.java:2905)
    at java.util.regex.Pattern.sequence(Pattern.java:2051)
    at java.util.regex.Pattern.expr(Pattern.java:1996)
    at java.util.regex.Pattern.group0(Pattern.java:2905)
    at java.util.regex.Pattern.sequence(Pattern.java:2051)
    at java.util.regex.Pattern.expr(Pattern.java:1996)
    at java.util.regex.Pattern.group0(Pattern.java:2905)
    at java.util.regex.Pattern.sequence(Pattern.java:2051)
    at java.util.regex.Pattern.expr(Pattern.java:1996)
    at java.util.regex.Pattern.compile(Pattern.java:1696)
    at java.util.regex.Pattern.<init>(Pattern.java:1351)
    at java.util.regex.Pattern.compile(Pattern.java:1028)
    at java.util.Scanner$1.create(Scanner.java:367)
    at java.util.Scanner$1.create(Scanner.java:365)
    at sun.misc.LRUCache.forName(LRUCache.java:72)
    at java.util.Scanner.integerPattern(Scanner.java:443)
    at java.util.Scanner.nextInt(Scanner.java:2117)
    at WeightCalc.main(Main.java:45)

倒数第二行：

java.util.Scanner.nextInt(Scanner.java:2117)

表明它在Scanner.nextInt。

Answer 2

您正在拨打错误的Scanner.readInt。您想要调用返回int的空args。

你调用的那个接受int作为输入，它应该是数字基数（即数字是八进制或二进制等）。由于feet和inches都被初始化为0，因此它会尝试读取基数0中的int，这是不可能的。

你想要的更像是：

// Ask for height, first feet, then inches 
System.out.println("What is your height in regards to feet? ");
feet = kboard.nextInt();
System.out.println("What is your remaining h eight in inches? ");
inches = kboard.nextInt();

索引525附近的未闭合字符类

2 个答案: