就是把昨天写的写成了爪哇，少了一些功能，，基本的在，牛逼的大牛可以拿去修改做的更好。
public boolean judge(char ch)//判断是不是字符数字{if(ch >= '0' && ch <= '9'){return true;}return false;}public String[] tochange(String s_1)//中缀表达式转换为后缀表达式{String S[] = new String[1000];StringBuffer numBuffer = new StringBuffer();Stack<String> s = new Stack<String>();int i = 0, j = 0;char ch;while(i != s_1.length()){ch = s_1.charAt(i);if(ch >= '0' && ch <= '9'){while (judge(ch)){numBuffer.append(ch);ch = s_1.charAt(++i);}S[j++] = numBuffer.toString();numBuffer = new StringBuffer();continue;}else if(ch == '('){s.push("(");}else if(ch == ')'){while(s.peek() != "("){S[j++] = s.pop();}s.pop();}else if(ch == '+' || ch == '-'){while(s.size() != 0 && s.peek() != "("){S[j++] = s.pop();}s.push(String.valueOf(ch));}else if(ch == '*' || ch == '/'){while(s.size() != 0 && (s.peek()== "*" || s.peek() == "/")){S[j++] = s.pop();}s.push(String.valueOf(ch));}i++;}while (s.size() != 0)S[j++] = s.pop();S[j] = "=";return S;}public int add(String s_1)//进行计算{String []sn = tochange(s_1);Stack<String>s = new Stack<String>();int i = 0,n = 0,m = 0,x = 0;char ch;while(sn[i] != "="){ch = sn[i].charAt(0);if(ch >= '0' && ch <= '9'){s.push(String.valueOf(sn[i]));}else if(ch == '+'){n = Integer.parseInt(s.pop());m = Integer.parseInt(s.pop());x = n + m;s.push(String.valueOf(x));}else if(ch == '-'){n = Integer.parseInt(s.pop());m = Integer.parseInt(s.pop());x = m – n;s.push(String.valueOf(x));}else if(ch == '*'){n = Integer.parseInt(s.pop());m = Integer.parseInt(s.pop());x = m * n;s.push(String.valueOf(x));}else if(ch == '/'){n = Integer.parseInt(s.pop());m = Integer.parseInt(s.pop());x = m / n;s.push(String.valueOf(x));}i++;}String ss = s.pop();int number = Integer.parseInt(ss);return number;}
学做任何事得按部就班，急不得
