java程序将整数转换为罗马数字时的运行时错误

在我的面向对象编程课程中，我们被要求修改一个转换1到3999之间整数的程序。我们不允许使用数组或循环。无论如何，下面是我的代码，它没有我能识别的错误，但是有一些东西阻止了程序成功运行。以下是将随机数（让我们使用100）放入短语“in.nextInt（）”时控制台上的显示：

“输入一个介于1和3999之间的数字开始：

线程“main”java.lang.StringIndexOutOfBoundsException中的异常： 字符串索引超出范围：100

这条信息的大部分对我来说都是胡言乱语，但我真的很难理解为什么当我的范围是1-3999时，数字100被解释为“超出范围”

Scanner in = new Scanner (System.in);
System.out.println("Enter a number between 1 and 3999 to begin: ");
int input = in.nextInt( );

    //we want to avoid 0, negative numbers & numbers greater than 3999
if (input < 1 || input > 3999);
    System.out.print("Invalid Number!");
    System.out.println("Please enter a number between 1 and 3999.");

        //creating strings to be defined for the different cases later
    String romanOnes = ("");
    String romanTens = ("");
    String romanHundreds = ("");
    String romanThousands = ("");

    //separating the ones, tens, hundreds & thousands from within the input
int ones1 = input % 10;
    int ones = ones1;

    int tens1 = input % 10;
        if (tens1 < 10)
        { tens1 = input / 10; }
        else
        { tens1 = (tens1 % 100) - ones; }

        int tens = tens1;

    int hundreds1 = input % 100;
        if (hundreds1 < 10)
        { hundreds1 = input / 100; }
        else
        { hundreds1 = (hundreds1 % 1000) - tens - ones; }

        int hundreds = hundreds1;

    int thousands1 = input % 1000;
        if (thousands1 < 4)
        { thousands1 = input / 1000; }
        else
        { thousands1 = (thousands1 % 10000) - hundreds - tens - ones; }

        int thousands = thousands1;

        // different cases for the "ones" and their conversion in to Roman numerals
    if (ones == 0)
        {romanOnes = ("");}
        while (ones == 1);
            {romanOnes = ("I");}
        while (ones == 2);
            {romanOnes = ("II");}   
        while (ones == 3);
            {romanOnes = ("III");}
        while (ones == 4);
            {romanOnes = ("IV");}
        while (ones == 5);                  
                            {romanOnes = ("V");}
        while (ones == 6);
            {romanOnes = ("VI");}
        while (ones == 7);
            {romanOnes = ("VII");}
        while (ones == 8);
            {romanOnes = ("VIII");}
        while (ones == 9);
            {romanOnes = ("IX");}   

            // different cases for the "tens" and their conversion in to Roman numerals
        if (tens == 0)
            {romanTens = ("");}
        while (tens == 1);
            {romanTens = ("X");}
        while (tens == 2);
            {romanTens = ("XX");}   
        while (tens == 3);
            {romanTens = ("XXX");}
        while (tens == 4);
            {romanTens = ("XL");}
        while (tens == 5);
            {romanTens = ("L");}
        while (tens == 6);
            {romanTens = ("LX");}
        while (tens == 7);
            {romanTens = ("LXX");}
        while (tens == 8);
            {romanTens = ("LXXX");}
        while (tens == 9);
            {romanTens = ("XC");}   

            // different cases for the "hundreds" and their conversion in to Roman numerals
        if (hundreds == 0)
            {romanHundreds = ("");}
        while (hundreds == 1);
            {romanHundreds = ("C");}
        while (hundreds == 2);
            {romanHundreds = ("CC");}   
        while (hundreds == 3);
            {romanHundreds = ("CCC");}
        while (hundreds == 4);
            {romanHundreds = ("CD");}
        while (hundreds == 5);
            {romanHundreds = ("D");}
        while (hundreds == 6);
            {romanHundreds = ("DC");}
        while (hundreds == 7);
            {romanHundreds = ("DCC");}
        while (hundreds == 8);
            {romanHundreds = ("DCCC");}
        while (hundreds == 9);
            {romanHundreds = ("CM");}   

            // different cases for the "thousands" and their conversion in to Roman numerals
        if (thousands == 0)
            {romanThousands = ("");}
        while (thousands == 1);
            {romanThousands = ("M");}
        while (thousands == 2);
            {romanThousands = ("MM");}  
        while (thousands == 3);
            {romanThousands = ("MMM");} 

            //Concatenating all strings to produce the complete Roman numeral
        String roman = (romanThousands + romanHundreds + romanTens + romanOnes);

            //output & goodbye message
        System.out.println(input + "in roman numerals is: " + roman);
        System.out.println("Thank you and goodbye!");   

}

}

Scanner-in=新的扫描仪（System.in）；
System.out.println（“输入一个介于1和3999之间的数字以开始：”）；
int input=in.nextInt（）；
//我们希望避免0、负数和大于3999的数字
如果（输入<1 | |输入>3999）；
系统输出打印（“无效数字！”）；
System.out.println（“请输入一个介于1和3999之间的数字”）；
//创建要在以后为不同情况定义的字符串
字符串romanOnes=（“”）；
字符串romanTens=（“”）；
字符串为（“”）；
字符串=（“”）；
//从输入中分离一、十、百和千
int ones1=输入%10；
int ones=ones1；
int tens1=输入%10；
if（时态1<10）
{tens1=input/10；}
其他的
{tens1=（tens1%100）-one；}
int-tens=tens1；
int hundreds1=输入%100；
如果（百分之一小于10）
{hundreds1=input/100；}
其他的
{hundreds1=（hundreds1%1000）-十位数；}
整数百=百分之一；
整数千分之一=输入%1000；
如果（千分之一小于4）
{000ands1=input/1000；}
其他的
{千分之一=（千分之一%10000）-百分之十；}
整数千=千1；
//“一”的不同格及其在罗马数字中的转换
如果（一=0）
{romanOnes=（“”）；}
而（一=1）；
{romanOnes=（“I”）；}
而（一=2）；
{romanOnes=（“II”）；}
而（一=3）；
{romanOnes=（“III”）；}
而（1==4）；
{romanOnes=（“IV”）；}
而（一=5）；
{romanOnes=（“V”）；}
而（1==6）；
{romanOnes=（“VI”）；}
而（1==7）；
{romanOnes=（“VII”）；}
而（1==8）；
{romanOnes=（“VIII”）；}
而（1==9）；
{romanOnes=（“IX”）；}
//“十”的不同情况及其在罗马数字中的转换
如果（十=0）
{romanTens=（“”）；}
而（十=1）；
{romanTens=（“X”）；}
而（十=2）；
{romanTens=（“XX”）；}
而（十=3）；
{romanTens=（“XXX”）；}
而（十=4）；
{romanTens=（“XL”）；}
而（十=5）；
{romanTens=（“L”）；}
而（十=6）；
{romanTens=（“LX”）；}
而（十=7）；
{romanTens=（“LXX”）；}
而（十=8）；
{romanTens=（“LXXX”）；}
而（十=9）；
{romanTens=（“XC”）；}
//“百”的不同格及其在罗马数字中的转换
如果（百分位==0）
{ROMAN=（“”）；}
而（百=1）；
{C=（“C”）；}
而(百分之二),；
{ROMAN=（“CC”）；}
而（百分之=3）；
{ROMAN=（“CCC”）；}
而(百分之四),；
{roman=（“CD”）；}
而(百分之五),；
{roman=（“D”）；}
而(百分之六),；
{ROMAN=（“DC”）；}
而(百分之七),；
{ROMAN=（“DCC”）；}
而(百分之八),；
{ROMAN=（“DCCC”）；}
而(百分之九),；
{CM=（“CM”）；}
//“千”的不同格及其在罗马数字中的转换
如果（千=0）
{ROMAN=（“”）；}
而（千=1）；
{roman=（“M”）；}
而（千=2）；
{roman=（“MM”）；}
而（千=3）；
{roman=（“MMM”）；}
//连接所有字符串以生成完整的罗马数字
字符串罗马=（罗马千+罗马百+罗马十+罗马一）；
//输出和再见消息
System.out.println（罗马数字中的输入+”为：“+罗马”；
System.out.println（“谢谢你，再见！”）；
}
}

---

提前感谢您的帮助

不允许使用数组或循环？可能会被告知您必须在建筑物的一侧用山羊血绘制程序。无论如何，您需要使用调试器。此“*胡言乱语”消息表示您正试图访问某个位置（

索引

）中的字符大于字符串长度。出于调试目的，请将

包装在.nextInt（）中；

包装在

if（in.hasNextInt）

语句中。您可能还需要发布整个

main

方法。“。。。当在短语“

in.nextInt（）

”中输入一个随机数（让我们使用100）时，请解释您实际做了什么：通过控制台输入100，或将其作为

in.nextInt（）

方法的参数。

Scanner in = new Scanner (System.in);
System.out.println("Enter a number between 1 and 3999 to begin: ");
int input = in.nextInt( );

    //we want to avoid 0, negative numbers & numbers greater than 3999
if (input < 1 || input > 3999);
    System.out.print("Invalid Number!");
    System.out.println("Please enter a number between 1 and 3999.");

        //creating strings to be defined for the different cases later
    String romanOnes = ("");
    String romanTens = ("");
    String romanHundreds = ("");
    String romanThousands = ("");

    //separating the ones, tens, hundreds & thousands from within the input
int ones1 = input % 10;
    int ones = ones1;

    int tens1 = input % 10;
        if (tens1 < 10)
        { tens1 = input / 10; }
        else
        { tens1 = (tens1 % 100) - ones; }

        int tens = tens1;

    int hundreds1 = input % 100;
        if (hundreds1 < 10)
        { hundreds1 = input / 100; }
        else
        { hundreds1 = (hundreds1 % 1000) - tens - ones; }

        int hundreds = hundreds1;

    int thousands1 = input % 1000;
        if (thousands1 < 4)
        { thousands1 = input / 1000; }
        else
        { thousands1 = (thousands1 % 10000) - hundreds - tens - ones; }

        int thousands = thousands1;

        // different cases for the "ones" and their conversion in to Roman numerals
    if (ones == 0)
        {romanOnes = ("");}
        while (ones == 1);
            {romanOnes = ("I");}
        while (ones == 2);
            {romanOnes = ("II");}   
        while (ones == 3);
            {romanOnes = ("III");}
        while (ones == 4);
            {romanOnes = ("IV");}
        while (ones == 5);                  
                            {romanOnes = ("V");}
        while (ones == 6);
            {romanOnes = ("VI");}
        while (ones == 7);
            {romanOnes = ("VII");}
        while (ones == 8);
            {romanOnes = ("VIII");}
        while (ones == 9);
            {romanOnes = ("IX");}   

            // different cases for the "tens" and their conversion in to Roman numerals
        if (tens == 0)
            {romanTens = ("");}
        while (tens == 1);
            {romanTens = ("X");}
        while (tens == 2);
            {romanTens = ("XX");}   
        while (tens == 3);
            {romanTens = ("XXX");}
        while (tens == 4);
            {romanTens = ("XL");}
        while (tens == 5);
            {romanTens = ("L");}
        while (tens == 6);
            {romanTens = ("LX");}
        while (tens == 7);
            {romanTens = ("LXX");}
        while (tens == 8);
            {romanTens = ("LXXX");}
        while (tens == 9);
            {romanTens = ("XC");}   

            // different cases for the "hundreds" and their conversion in to Roman numerals
        if (hundreds == 0)
            {romanHundreds = ("");}
        while (hundreds == 1);
            {romanHundreds = ("C");}
        while (hundreds == 2);
            {romanHundreds = ("CC");}   
        while (hundreds == 3);
            {romanHundreds = ("CCC");}
        while (hundreds == 4);
            {romanHundreds = ("CD");}
        while (hundreds == 5);
            {romanHundreds = ("D");}
        while (hundreds == 6);
            {romanHundreds = ("DC");}
        while (hundreds == 7);
            {romanHundreds = ("DCC");}
        while (hundreds == 8);
            {romanHundreds = ("DCCC");}
        while (hundreds == 9);
            {romanHundreds = ("CM");}   

            // different cases for the "thousands" and their conversion in to Roman numerals
        if (thousands == 0)
            {romanThousands = ("");}
        while (thousands == 1);
            {romanThousands = ("M");}
        while (thousands == 2);
            {romanThousands = ("MM");}  
        while (thousands == 3);
            {romanThousands = ("MMM");} 

            //Concatenating all strings to produce the complete Roman numeral
        String roman = (romanThousands + romanHundreds + romanTens + romanOnes);

            //output & goodbye message
        System.out.println(input + "in roman numerals is: " + roman);
        System.out.println("Thank you and goodbye!");   

}

}