好吧，经过如此多的讨论和如此多的代码问题，我已经完全修改了原始代码，因为您说过您想了解更多。除其他改进外，我还进行了以下更改：
- Meaninfgul类别名称
- 有意义的方法和参数名称
- 出于简洁的代码原因（文档，一处轻松更改，有意义的名称），运行时优化），将重复且经常使用的常数（例如，
50
和数字的数组表示形式1
）（需要否定）转换为静态最终成员。 - 扩展代码以允许负整数作为操作数
- 添加了用于用户输入的验证模式。例如，现在检查最大数字长度，以避免数组溢出。
- 通过使数组大于用户输入允许的最大位数来避免计算过程中的数值溢出（请参阅源代码注释）
- 添加带有操作数和操作员输入错误处理的重试循环，将控制台处理提取到一种参数化方法中。
- 通过删除不必要的检查来简化代码，因为在将用户输入转换为之前，已经对其进行了验证
int[]
。 - 使调试输出为可选
package de.scrum_master.stackoverflow; import java.util.Arrays; import java.util.Scanner; import java.util.regex.Pattern; public class TensComplementArithmetic { // Print debug messages? private static final boolean DEBUG = true; // Maximum length for numbers entered by a user // (number of digits excluding the optional +/- sign) private static final int MAX_NUMBER_LENGTH = 50; // Array must have one additional element for the sign and // one more to avoid overflows when adding big negative numbers private static final int ARRAY_LENGTH = MAX_NUMBER_LENGTH + 2; // Scanner for console input handling private static final Scanner INPUT_SCANNER = new Scanner(System.in); // Regex pattern for positive/negative integer number format verification incl. length check private static final Pattern INTEGER_PATTERN = Pattern.compile("[+-]?[0-9]{1," + MAX_NUMBER_LENGTH + "}"); // Regex pattern for operator verification (currently only "+"/"-" allowed) private static final Pattern OPERATOR_PATTERN = Pattern.compile("[+-]"); // The number 1 is always needed for converting a 9's into a 10's complement // during negation, so we define it as a reusable constant private static final int[] NUMBER_ONE; static { // Initialise constant carrying array representation for number 1 NUMBER_ONE = new int[ARRAY_LENGTH]; NUMBER_ONE[ARRAY_LENGTH - 1] = 1; } public static String readConsoleInput(String prompt, Pattern validationPattern, String errorMessage) { String input = null; while (input == null) { System.out.print(prompt + ": "); if (INPUT_SCANNER.hasNext(validationPattern)) input = INPUT_SCANNER.next(validationPattern); else { INPUT_SCANNER.nextLine(); System.out.println(errorMessage); } } return input; } public static String getOperand(String operandName) { return readConsoleInput( "Operand " + operandName, INTEGER_PATTERN, "Illegal number format, please enter a positive/negative integer of max. " + MAX_NUMBER_LENGTH + " digits." ); } private static String getOperator() { return readConsoleInput( "Arithmetical operator (+ or -)", OPERATOR_PATTERN, "Unknown operator, try again." ); } public static int[] parseInteger(String number) { char sign = number.charAt(0); boolean isNegative = sign == '-' ? true : false; if (isNegative || sign == '+') number = number.substring(1); int[] result = new int[ARRAY_LENGTH]; int parsePosition = number.length() - 1; for (int i = result.length - 1; i >= 0; i--) { if (parsePosition < 0) break; result[i] = number.charAt(parsePosition--) - '0'; } return isNegative ? negate(result) : result; } public static int[] add(int[] operand1, int[] operand2) { int[] result = new int[ARRAY_LENGTH]; int carry = 0; for (int i = ARRAY_LENGTH - 1; i >= 0; i--) { result[i] = operand1[i] + operand2[i] + carry; if (result[i] >= 10) { result[i] = result[i] % 10; carry = 1; } else carry = 0; } return result; } public static int[] complement(int[] operand) { int[] result = new int[ARRAY_LENGTH]; for (int i = operand.length - 1; i >= 0; i--) result[i] = 9 - operand[i]; return result; } public static int[] negate(int[] operand) { return add(complement(operand), NUMBER_ONE); } public static void print(int[] result, String operation) { System.out.print(operation.charAt(0) == '-' ? "Difference = " : "Sum = "); if (result[0] == 9) { result = negate(result); System.out.print("-"); } boolean leadingZero = true; for (int i = 0; i < result.length; i++) { if (leadingZero) { if (result[i] == 0) continue; leadingZero = false; } System.out.print(result[i]); } System.out.println(leadingZero ? "0" : ""); } public static void main(String[] args) { int[] operand1 = parseInteger(getOperand("#1")); int[] operand2 = parseInteger(getOperand("#2")); String operator = getOperator(); if (operator.equals("-")) operand2 = negate(operand2); int[] result = new int[ARRAY_LENGTH]; result = add(operand1, operand2); if (DEBUG) { System.out.println("Operand #1 = " + Arrays.toString(operand1)); System.out.println("Operand #2 = " + Arrays.toString(operand2)); System.out.println("Result = " + Arrays.toString(result)); } print(result, operator); } }
