从C语言转换过来的Java版，字符串代数运算器

本文所写的代码，是根据这个帖子，自己手动转换过来滴。

在这个帖子中，我已经做了回复，但是，发现这个代码，并不能正确的运行，于是进行了修改。

原贴地址：http://topic.youkuaiyun.com/u/20090717/14/c99b9d35-acdc-4697-afc0-3b55093d4e65.html

 

所翻译过来的代码如下：

package houlei.csdn.util; import java.util.Stack; /** * 该类创建于 2009-7-20 下午04:29:30 * * @version 1.0.0 * @author 侯磊 */ public class StringResolution { public static final double DERROR = 0.0000001d;// 浮点数的精度。 public static final double BIGNUMBER = 0.0d; static class Operand { public int startIndex = 0; // start index which in formula public boolean isConst = false; // TRUE when it is digital, FALSE otherwise public String name=""; // digital string or variant name public Operand() { } public Operand(int startIndex, boolean isConst, String name) { this.startIndex = startIndex; this.isConst = isConst; this.name = name; } @Override public boolean equals(Object obj) { if(obj==null)return false; if(this==obj)return true; if (obj instanceof Operand) { Operand od = (Operand) obj; return (isConst == od.isConst) && (name.equals(od.name)); } return false; } } static class Operator { public int level; // 优先级 //or - 1 // and - 2 // == <> - 3 // > >= < <= 4 // +,- 5 // *,/,% 6 // ^ 7 // function 8 // not 9 // -,+ 10 public byte op; // 具体的操作 public byte type; // 0--单目运算, 1--双目运算 public int startIndex; // start index which in formula public static final int LEVELS = 55;// public static final int UNARY = 0;// 0--单目运算 public static final int BINARY = 1;// 1--双目运算 public static final byte OP_OR = 1; public static final byte OP_AND = 2; public static final byte OP_EQUAL = 3; public static final byte OP_NOTEQUAL = 4; public static final byte OP_GT = 5; public static final byte OP_GE = 6; public static final byte OP_LT = 7; public static final byte OP_LE = 8; public static final byte OP_ADD = 9; public static final byte OP_SUB = 10; public static final byte OP_MUL = 11; public static final byte OP_DIV = 12; public static final byte OP_MOD = 13; public static final byte OP_MMUL = 14; public static final byte OP_FUNC = 15; public static final byte OP_NOT = 16; public static final byte OP_NEG = 17; public static final byte OP_POS = 18; public static final byte OP_ASSIGN = 19; } static boolean IsDigit(char ch) { return Character.isDigit(ch); } static boolean IsZero(double d) { return d < DERROR || d > -DERROR; } static int BooleanToInt(boolean b) { return b ? 1 : 0; } private int oprandNum = 0;// operand number private int oprandANum = 0;// variant number private int operatorNum = 0;// operator number private char[] dstname = null; // 赋值变量名 private String formula = null; // formula string private Operator operator[] = null;// pointer points to operators set private Operand oprand[] = null;// pointer points to operands set private Operand oprandA[] = null;// pointer points to variants set public StringResolution(String formula) { if (formula != null) { this.formula = formula.toUpperCase(); initialize(); } } private void initialize() { Stack<Operator> Op = getOperatorStack(); Stack<Operand> Od = getOperandStack(); if (Od == null || Op == null) { return; } oprandNum = Od.size(); operatorNum = Op.size(); if (operatorNum != 0) operator = new Operator[operatorNum]; if (oprandNum != 0) oprand = new Operand[oprandNum]; int i; for (i = 0; i < operatorNum; i++) { Operator op = (Operator) Op.peek(); operator[operatorNum - i - 1] = op; Op.pop(); op = null; } for (i = 0; i < oprandNum; i++) { Operand od = (Operand) Od.peek(); oprand[oprandNum - i - 1] = od; Od.pop(); od = null; } oprandA = new Operand[oprandNum]; boolean IsIn = false; for (i = 0; i < oprandNum; i++) { for (int j = 0; j < oprandANum; j++) { if (oprand[i].equals(oprandA[j])) { IsIn = true; break; } } if (!IsIn && !oprand[i].isConst) { oprandA[oprandANum] = oprand[i]; oprandANum++; } IsIn = false; } // System.out.println();; } private Stack<Operand> getOperandStack() { Stack<Operand> oprStack = new Stack<Operand>(); int i = 0; int num = formula.length(); while (i < num) { if (formula.charAt(i) == '#' || formula.charAt(i) == '@' || formula.charAt(i) == ' ' || formula.charAt(i) == '/t') i++; else { Operand oprand = new Operand(); if (IsDigit(formula.charAt(i))) oprand.isConst = true; oprand.startIndex = i; boolean HasPoint = false; while (i < num && formula.charAt(i) != '#' && formula.charAt(i) != '@') { if (formula.charAt(i) == '.') { if (HasPoint) { oprand = null; return null; } else HasPoint = true; } if (oprand.isConst && !IsDigit(formula.charAt(i)) && (formula.charAt(i) != '.')) { oprand = null; return null; } oprand.name += formula.charAt(i); i++; } oprStack.push(oprand); } } return oprStack; } private Stack<Operator> getOperatorStack() { Stack<Operator> operStack = new Stack<Operator>(); char buff[] = new char[formula.length()]; formula.getChars(0, buff.length, buff, 0); Operator op = null; int i = 0; int level = 0; while (i < buff.length) { switch (buff[i]) { case '(': level += Operator.LEVELS; buff[i] = '#'; i++; break; case ')': level -= Operator.LEVELS; buff[i] = '@'; i++; break; case '+': case '-': op = new Operator(); op.level = level + 5; op.startIndex = i; if (i == 0 || buff[i - 1] == '#') { op.type = Operator.UNARY; op.level += 5; if (buff[i] == '-') op.op = Operator.OP_NEG; else op.op = Operator.OP_POS; } else { op.type = Operator.BINARY; if (buff[i] == '-') op.op = Operator.OP_SUB; else op.op = Operator.OP_ADD; } operStack.push(op); buff[i] = '@'; i++; break; case '*': case '/': case '%': op = new Operator(); op.level = level + 6; if (buff[i] == '*') op.op = Operator.OP_MUL; else if (buff[i] == '/') op.op = Operator.OP_DIV; else op.op = Operator.OP_MOD; op.startIndex = i; op.type = Operator.BINARY; operStack.push(op); buff[i] = '@'; i++; break; case '^': op = new Operator(); op.level = level + 7; op.op = Operator.OP_MMUL; op.startIndex = i; op.type = Operator.BINARY; operStack.push(op); buff[i] = '@'; i++; break; case 'a': if (i + 2 < buff.length && buff[i + 1] == 'n' && buff[i + 2] == 'd') { op = new Operator(); op.level = level + 2; op.op = Operator.OP_AND; op.startIndex = i; op.type = Operator.BINARY; operStack.push(op); buff[i] = '@'; buff[i + 1] = '@'; buff[i + 2] = '@'; i += 3; } break; case 'o': if (i + 1 < buff.length && buff[i + 1] == 'r') { op = new Operator(); op.level = level + 1; op.op = Operator.OP_OR; op.startIndex = i; op.type = Operator.BINARY; operStack.push(op); buff[i] = '@'; buff[i + 1] = '@'; i += 2; } break; case 'n': if (i + 2 < buff.length && buff[i + 1] == 'o' && buff[i + 2] == 't') { op = new Operator(); op.level = level + 9; op.op = Operator.OP_NOT; op.startIndex = i; op.type = Operator.UNARY; operStack.push(op); buff[i] = '@'; buff[i + 1] = '@'; buff[i + 2] = '@'; i += 3; } break; case '>': op = new Operator(); op.level = level + 4; op.startIndex = i; op.type = Operator.BINARY; buff[i] = '@'; operStack.push(op); if (i + 1 < buff.length && buff[i + 1] == '=') { op.op = Operator.OP_GE; buff[i + 1] = '@'; i += 2; } else { op.op = Operator.OP_GT; i += 1; } break; case '<': op = new Operator(); op.startIndex = i; op.type = Operator.BINARY; buff[i] = '@'; operStack.push(op); if (i + 1 < buff.length && buff[i + 1] == '=') { op.level = level + 4; op.op = Operator.OP_LE; buff[i + 1] = '@'; i += 2; break; } if (i + 1 < buff.length && buff[i + 1] == '>') { op.level = level + 3; op.op = Operator.OP_NOTEQUAL; buff[i + 1] = '@'; i += 2; break; } op.level = level + 4; op.op = Operator.OP_LT; i += 1; break; case '=': if (i + 1 < buff.length && buff[i + 1] == '=') { op = new Operator(); op.level = level + 3; op.op = Operator.OP_EQUAL; op.startIndex = i; op.type = Operator.BINARY; operStack.push(op); buff[i] = '@'; buff[i + 1] = '@'; i += 2; break; } int lastpos = 0; op = operStack.peek(); // new Operator(); if (op != null) lastpos = op.startIndex; int ii = i - lastpos + 1; dstname = new char[ii]; System.arraycopy(buff, lastpos, dstname, 0, ii - 1); ii = buff.length; System.arraycopy(buff, i + 1, buff, lastpos, ii - i - 1); buff[lastpos + ii - i - 1] = 0; char temp[] = new char[lastpos + ii - i]; System.arraycopy(buff, 0, temp, 0, temp.length); buff = temp; i = lastpos; break; default: i++; } } formula = new String(buff); return operStack; } public double computer(double variantValue[], int num) { double value = 0.0d; int i; if (num < oprandANum) { return BIGNUMBER; } Stack<Operator> operStack = new Stack<Operator>(); Stack<Operand> oprStack = new Stack<Operand>(); for (i = 0; i < operatorNum; i++) { operStack.push(operator[operatorNum - i - 1]); } for (i = 0; i < oprandNum; i++) { Operand od = oprandA[oprandNum - i - 1]; for (int j = 0; j < oprandANum; j++) { if (od.equals(oprandA[j])) { od.name = String.valueOf(variantValue[j]); } } oprStack.push(od); } value = computer(operStack, oprStack); return value; } private double computer(Stack<Operator> operStack, Stack<Operand> oprStack) { double value = 0.0d; if (operStack.empty()) { if (oprStack.size() == 1) { Operand od = oprStack.peek(); value = Double.parseDouble(od.name); od = null; return value; } else { if (!oprStack.empty()) { oprStack.clear(); } return BIGNUMBER; } } Stack<Operator> tmpOO = new Stack<Operator>(); Stack<Operand> tmpOD = new Stack<Operand>(); Operator op = null, op1 = null; Operand oprand = null, oprand1 = null; op = operStack.pop(); if (!operStack.empty()) op1 = operStack.peek(); while (op1 != null && (op1.level > op.level)) { tmpOO.push(op); if (op.type == Operator.BINARY) { if (!oprStack.empty()) { oprand = oprStack.pop(); tmpOD.push(oprand); } } op = op1; operStack.pop(); if (!operStack.empty()) op1 = (Operator) operStack.peek(); else op1 = null; } if (op.type == Operator.UNARY) { if (oprStack.empty()) { return BIGNUMBER; } oprand = oprStack.peek(); double x = computing(op, oprand); oprand.name = String.valueOf(x); // FLOATTOWSTR(x,szstr,32); // WSTRTOSTR(szstr,oprand.m_name,16); } else { if (oprStack.empty()) { return BIGNUMBER; } oprand1 = oprStack.pop(); if (oprStack.empty()) { return BIGNUMBER; } oprand = oprStack.peek(); double x = computing(op, oprand1, oprand); oprand.name = String.valueOf(x); // FLOATTOWSTR(x,szstr,32); // WSTRTOSTR(szstr,oprand.m_name,16); oprand1 = null; } op = null; while (!tmpOO.empty()) { op = tmpOO.pop(); operStack.push(op); } while (!tmpOD.empty()) { oprand = tmpOD.pop(); oprStack.push(oprand); } return computer(operStack, oprStack); } private double computing(final Operator op, final Operand Loprand, final Operand Roprand) { double x = BIGNUMBER; switch (op.op) { case Operator.OP_OR: { int i1 = Integer.parseInt(Loprand.name); int i2 = Integer.parseInt(Roprand.name); x = BooleanToInt((i1 != 0 || i2 != 0)); // x = BooleanToInt((int)(i1 || i2)); } break; case Operator.OP_AND: { int i1 = Integer.parseInt(Loprand.name); int i2 = Integer.parseInt(Roprand.name); x = BooleanToInt((i1 != 0 && i2 != 0)); } break; case Operator.OP_EQUAL: { double i1 = Double.parseDouble(Loprand.name); double i2 = Double.parseDouble(Roprand.name); boolean i = (Double.compare(i1, i2) == 0); x = BooleanToInt(i); } break; case Operator.OP_NOTEQUAL: { double i1 = Double.parseDouble(Loprand.name); double i2 = Double.parseDouble(Roprand.name); boolean i = (Double.compare(i1, i2) != 0); x = BooleanToInt(i); } break; case Operator.OP_GT: { double i1 = Double.parseDouble(Loprand.name); double i2 = Double.parseDouble(Roprand.name); boolean i = (Double.compare(i1, i2) > 0); x = BooleanToInt(i); } break; case Operator.OP_GE: { double i1 = Double.parseDouble(Loprand.name); double i2 = Double.parseDouble(Roprand.name); boolean i = (Double.compare(i1, i2) >= 0); x = BooleanToInt(i); } break; case Operator.OP_LT: { double i1 = Double.parseDouble(Loprand.name); double i2 = Double.parseDouble(Roprand.name); boolean i = (Double.compare(i1, i2) < 0); x = BooleanToInt(i); } break; case Operator.OP_LE: { double i1 = Double.parseDouble(Loprand.name); double i2 = Double.parseDouble(Roprand.name); boolean i = (Double.compare(i1, i2) <= 0); x = BooleanToInt(i); } break; case Operator.OP_ADD: x = Double.parseDouble(Loprand.name) + Double.parseDouble(Roprand.name); break; case Operator.OP_SUB: x = Double.parseDouble(Loprand.name) - Double.parseDouble(Roprand.name); break; case Operator.OP_MUL: x = Double.parseDouble(Loprand.name) * Double.parseDouble(Roprand.name); break; case Operator.OP_DIV: { double d1 = Double.parseDouble(Loprand.name); double d2 = Double.parseDouble(Roprand.name); if (!IsZero(d2)) { x = d1 / d2; } } break; default: break; } return x; } private double computing(final Operator op, final Operand oprand) { double x = Double.parseDouble(oprand.name); if (op.op == Operator.OP_NEG) { x = -x; } else if (op.op == Operator.OP_POS) { ; } else if (op.op == Operator.OP_ASSIGN) { // oprand=(COperand*)Oprand.top(); // DBGPRINTF("%d,%s",op->m_op,oprand->m_name); } else if (op.op == Operator.OP_NOT) { int b = Integer.parseInt(oprand.name) == 0 ? 1 : 0; // boolean b = ATOI(oprand.m_name); // b = !b; x = b; } return x; } public int getVariantCount() { return oprandANum; } public static void main(String args []){ String formula = "c==a+b"; StringResolution sr = new StringResolution(formula); double variantValue [] = new double[]{0.0,0.0,0.0}; System.out.println(sr.computer(variantValue, sr.getVariantCount())); } }