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java - 字符串加减法程序

问题描述

我写了一个程序，我想对字符串进行加法和减法，其中所有字符串的长度都是四，看起来像“+002”、“+569”、“-022”、“-789”等。我'试图在不使用任何乘法、除法或余数的情况下做到这一点，但只使用加法和减法作为运算，但我的问题是某些情况还不起作用，我不明白为什么或如何解决它因为用这么长的代码很难看清问题到底出在哪里以及我应该改变什么。所以这里是有关的方法：

public static String add(String s1, String s2) {
        int number;
        int[] s = new int[4];
        String result = "";
        if (s1.contains("+") && s2.contains("+")) {
            result = "+";
            for (int i = 1; i < s1.length(); ++i) {
                if (!(s1.charAt(i) == 0 || s2.charAt(i) == 0)) {
                    if ((int) (s1.charAt(i)) + (int) (s2.charAt(i)) - 96 < 10) s[i] = (int) (s1.charAt(i)) + (int) (s2.charAt(i)) - 96;
                    else {
                        s[i] = (s1.charAt(i)) + (int) (s2.charAt(i)) - 106;
                    ++s[i - 1];
                    }
                }
                else if (s1.charAt(i) != 0 && s2.charAt(i) != 0) {
                    s[i] = (int) (s1.charAt(i)) + (int) (s2.charAt(i)) - 96;
                }
            }
        }
        else if (s1.contains("-") && s1.contains("-")) {
            result = "-";
            for (int i = 1; i < s1.length(); ++i) {
                if ((!(s1.charAt(i) == 0 || s2.charAt(i) == 0))) {
                    if ((int) (s1.charAt(i)) + (int) (s2.charAt(i)) - 96 < 10) s[i] = (int) (s1.charAt(i)) + (int) (s2.charAt(i)) - 96;
                    else {
                        s[i] = (s1.charAt(i)) + (int) (s2.charAt(i)) - 106;
                    ++s[i - 1];
                    }
                }
                else if (s1.charAt(i) != 0 && s2.charAt(i) != 0) {
                    s[i] = (int) (s1.charAt(i)) + (int) (s2.charAt(i)) - 96;
                }
            }
        }
        //if (s1.contains("+") && s1.contains("-") || s1.contains("-") && s1.contains("+"))
        else if (s1.contains("+") && s2.contains("-")) {
            char[] size1 = new char[s1.length()];
            char[] size2 = new char[s1.length()];
            for (int i = 1; i < s1.length(); ++i) {
                size1[i] = s1.charAt(i); 
                size2[i] = s2.charAt(i); 
            }
            if (size1[1] > size2[1]) result = "+";
            else if (size1[1] == size2[1]) {
                if (size1[2] > size2[2]) result = "+";
                else if (size1[2] == size2[2]) {
                    if (size1[3] > size2[3]) result = "+";
                    else if (size1[3] == size2[3]) return "+000";
                    else result = "-";
                }
                else result = "-";
            }
            else result = "-";
            for (int i = 1; i < s1.length(); ++i) {
                if (!(s1.charAt(i) == 0 || s2.charAt(i) == 0)) {
                    if (s1.charAt(1) < s2.charAt(1)) {
                        if (s1.charAt(2) <= s2.charAt(2)) {
                            if (s1.charAt(3) > s2.charAt(3)) {
                                s[2] = 10 - (s2.charAt(2) - s1.charAt(2));
                                s[3] = 10 - (s1.charAt(3) - s2.charAt(3));
                                --s[2];
                                s[1] = (s2.charAt(1) - s1.charAt(1));
                            }
                            else {
                                s[2] = (s2.charAt(2) - s1.charAt(2));
                                s[3] = (s2.charAt(3) - s1.charAt(3));
                                s[1] = s2.charAt(1) - s1.charAt(1);
                            }
                        }
                        else {
                            s[2] = 10 - (s1.charAt(2) - s2.charAt(2));
                            if (s1.charAt(3) < s2.charAt(3)) s[3] = (s2.charAt(3) - s1.charAt(3));
                            else {
                                s[3] = 10 - (s1.charAt(3) - s2.charAt(3));
                                --s[2];
                            }
                        }
                    }
                    else if (s1.charAt(i) - s2.charAt(i) < 0 && i == 1) s[i] = s2.charAt(i) - s1.charAt(i);
                    else if (s1.charAt(i) - s2.charAt(i) < 0 && i > 1) {
                        s[i] = s2.charAt(i) - s1.charAt(i);
                    }
                    else s[i] = s1.charAt(i) - s2.charAt(i);
                }
            }
        }
        else {
            char[] size1 = new char[s1.length()];
            char[] size2 = new char[s1.length()];
            for (int i = 1; i < s1.length(); ++i) {
                size1[i] = s1.charAt(i); 
                size2[i] = s2.charAt(i); 
            }
            if (size1[1] < size2[1]) result = "+";
            else if (size1[1] == size2[1]) {
                if (size1[2] < size2[2]) result = "+";
                else if (size1[2] == size2[2]) {
                    if (size1[3] < size2[3]) result = "+";
                    else if (size1[3] == size2[3]) return "+000";
                    else result = "-";
                }
                else result = "-";
            }
            else result = "-";
            for (int i = 1; i < s1.length(); ++i) {
                if (!(s1.charAt(i) == 0 || s2.charAt(i) == 0)) {
                    if (s1.charAt(1) > s2.charAt(1)) {
                        if (s1.charAt(2) >= s2.charAt(2)) {
                            if (s1.charAt(3) < s2.charAt(3)) {
                                s[2] = 10 - (s1.charAt(2) - s2.charAt(2));
                                s[3] = 10 - (s2.charAt(3) - s1.charAt(3));
                                --s[2];
                            }
                            else {
                                s[2] = (s1.charAt(2) - s2.charAt(2));
                                s[3] = (s1.charAt(3) - s2.charAt(3));
                                s[1] = s1.charAt(1) - s2.charAt(1);
                            }
                        }
                    }
                    else if (s1.charAt(i) - s2.charAt(i) > 0 && i == 1) s[i] = s1.charAt(i) - s2.charAt(i);
                    else if (s1.charAt(i) - s2.charAt(i) > 0 && i > 1) {
                        s[i] = s1.charAt(i) - s2.charAt(i);
                    }
                    else s[i] = s2.charAt(i) - s1.charAt(i);
                }
            }
        }
        for (int i = 1; i < s.length; ++i) result += s[i];
        return result;
    }

标签： javastringcharintcharat

解决方案

由于您可以使用 charAt()，因此您可以自行转换字符串：

// String s1 = "+123";
int d1 = (s1.charAt(1) - '0') * 100;
int d2 = (s1.charAt(2) - '0') * 10;
int d3 = (s1.charAt(3) - '0');
int num = d1 + d2 + d3;

然后你可以用这个数字计算。

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