说明：
我希望用c#和c++写一个脚本解释器，用于科学运算
效果图：
step1: c#
C:\Users\wangrusheng\RiderProjects\WinFormsApp3\WinFormsApp3\Form1.cs
using System;
using System.Collections.Generic;
using System.Data;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows.Forms;namespace WinFormsApp3;public partial class Form1 : Form
{private Dictionary<string, double> variables = new Dictionary<string, double>();// Windows Forms 设计器代码private TextBox txtScript;private Button btnExecute;private TextBox txtOutput;public Form1(){InitializeComponent();this.txtScript = new TextBox();this.btnExecute = new Button();this.txtOutput = new TextBox();this.SuspendLayout();// txtScriptthis.txtScript.Multiline = true;this.txtScript.Location = new System.Drawing.Point(12, 12);this.txtScript.Size = new System.Drawing.Size(400, 150);this.txtScript.ScrollBars = ScrollBars.Vertical;// btnExecutethis.btnExecute.Location = new System.Drawing.Point(12, 170);this.btnExecute.Size = new System.Drawing.Size(75, 23);this.btnExecute.Text = "执行";this.btnExecute.Click += new System.EventHandler(this.btnExecute_Click);// txtOutputthis.txtOutput.Multiline = true;this.txtOutput.Location = new System.Drawing.Point(12, 200);this.txtOutput.Size = new System.Drawing.Size(400, 150);this.txtOutput.ScrollBars = ScrollBars.Vertical;this.txtOutput.ReadOnly = true;// MainFormthis.ClientSize = new System.Drawing.Size(424, 361);this.Controls.Add(this.txtOutput);this.Controls.Add(this.btnExecute);this.Controls.Add(this.txtScript);this.Text = "简单脚本解释器";this.ResumeLayout(false);this.PerformLayout();}private void btnExecute_Click(object sender, EventArgs e){variables.Clear();txtOutput.Clear();string[] lines = txtScript.Text.Split(new[] { "\r\n", "\r", "\n" }, StringSplitOptions.RemoveEmptyEntries);foreach (string line in lines){try{var result = ProcessLine(line.Trim());if (!string.IsNullOrEmpty(result)){txtOutput.AppendText(result + "\r\n");}}catch (Exception ex){txtOutput.AppendText($"错误: {ex.Message}\r\n");}}}private string ProcessLine(string line){if (string.IsNullOrWhiteSpace(line)) return "";// 处理赋值语句if (line.Contains("=")){var match = Regex.Match(line, @"^\s*([a-zA-Z_]\w*)\s*=\s*(.+?)\s*$");if (!match.Success) throw new ArgumentException("无效的赋值语句");string varName = match.Groups[1].Value;double value = EvaluateExpression(match.Groups[2].Value);variables[varName] = value;return $"{varName} = {value}";}// 处理普通表达式return EvaluateExpression(line).ToString();}private double EvaluateExpression(string expr){// 替换变量为实际值string resolvedExpr = Regex.Replace(expr, @"\b([a-zA-Z_]\w*)\b", match =>{string varName = match.Groups[1].Value;if (variables.TryGetValue(varName, out double value)){return value.ToString();}throw new ArgumentException($"未定义的变量: {varName}");});// 计算数学表达式DataTable table = new DataTable();table.Columns.Add("expr", typeof(string), resolvedExpr);DataRow row = table.NewRow();table.Rows.Add(row);return Convert.ToDouble(row["expr"]);}}
step2: C++代码 C:\Users\wangrusheng\CLionProjects\untitled28\main.cpp
#include <iostream>
#include <string>
#include <map>
#include <regex>
#include <cctype>
#include <vector>
#include <algorithm>
#include <sstream>
#include <stdexcept>using namespace std;map<string, double> variables;// 辅助函数：跳过空白字符
void skip_whitespace(const string& expr, size_t& pos) {while (pos < expr.size() && isspace(expr[pos])) pos++;
}// 表达式解析函数声明
double eval_expression(const string& expr, size_t& pos);
double eval_term(const string& expr, size_t& pos);
double eval_factor(const string& expr, size_t& pos);
double eval_primary(const string& expr, size_t& pos);// 主解析函数
double evaluate(const string& expr) {size_t pos = 0;double result = eval_expression(expr, pos);skip_whitespace(expr, pos);if (pos != expr.size()) {throw runtime_error("Unexpected characters in expression");}return result;
}// 表达式解析实现
double eval_expression(const string& expr, size_t& pos) {return eval_term(expr, pos);
}double eval_term(const string& expr, size_t& pos) {double left = eval_factor(expr, pos);skip_whitespace(expr, pos);while (pos < expr.size()) {char op = expr[pos];if (op != '+' && op != '-') break;pos++;double right = eval_factor(expr, pos);if (op == '+') left += right;else left -= right;skip_whitespace(expr, pos);}return left;
}double eval_factor(const string& expr, size_t& pos) {double left = eval_primary(expr, pos);skip_whitespace(expr, pos);while (pos < expr.size()) {char op = expr[pos];if (op != '*' && op != '/') break;pos++;double right = eval_primary(expr, pos);if (op == '*') left *= right;else {if (right == 0) throw runtime_error("Division by zero");left /= right;}skip_whitespace(expr, pos);}return left;
}double eval_primary(const string& expr, size_t& pos) {skip_whitespace(expr, pos);if (pos >= expr.size()) {throw runtime_error("Unexpected end of expression");}if (expr[pos] == '(') {pos++;double value = eval_expression(expr, pos);skip_whitespace(expr, pos);if (pos >= expr.size() || expr[pos] != ')') {throw runtime_error("Missing closing parenthesis");}pos++;return value;}if (expr[pos] == '+' || expr[pos] == '-') {bool negative = (expr[pos] == '-');pos++;double value = eval_primary(expr, pos);return negative ? -value : value;}if (isdigit(expr[pos]) || expr[pos] == '.') {size_t start = pos;bool has_decimal = false;while (pos < expr.size() && (isdigit(expr[pos]) || expr[pos] == '.')) {if (expr[pos] == '.') {if (has_decimal) throw runtime_error("Invalid number format");has_decimal = true;}pos++;}return stod(expr.substr(start, pos - start));}throw runtime_error("Unexpected character: " + string(1, expr[pos]));
}// 变量替换函数
string replace_variables(const string& expr) {regex var_re(R"(\b([a-zA-Z_]\w*)\b)");smatch match;string result;size_t last = 0;auto begin = expr.cbegin();while (regex_search(begin, expr.cend(), match, var_re)) {result += string(begin, begin + match.position());string var = match[1];if (!variables.count(var)) {throw runtime_error("Undefined variable: " + var);}result += to_string(variables[var]);begin += match.position() + match.length();last = begin - expr.begin();}result += expr.substr(last);return result;
}// 处理单行输入
void process_line(const string& line) {try {string trimmed = line;trimmed.erase(remove_if(trimmed.begin(), trimmed.end(), ::isspace), trimmed.end());if (trimmed.empty()) return;// 处理赋值语句smatch match;regex assign_re(R"(^([a-zA-Z_]\w*)=(.*)$)");if (regex_match(trimmed, match, assign_re)) {string var = match[1];string expr = replace_variables(match[2]);variables[var] = evaluate(expr);cout << var << " = " << variables[var] << endl;}// 处理普通表达式else {string expr = replace_variables(trimmed);double result = evaluate(expr);cout << result << endl;}} catch (const exception& e) {cerr << "Error: " << e.what() << endl;}
}int main() {cout << "Simple C++ Script Interpreter (type 'exit' to quit)" << endl;string line;while (true) {cout << "> ";getline(cin, line);if (line == "exit") break;process_line(line);}return 0;
}
step3:运行
C:\Users\wangrusheng\CLionProjects\untitled28\cmake-build-debug\untitled28.exe
Simple C++ Script Interpreter (type 'exit' to quit)
>a=5*3a = 15
>b=a*2b = 30
>c=5/0>Error: Division by zero
a=9a = 9
>88
>3/4*((2-(5/6))/(7/12)+(1/3)*(9/5)-(2/15))1.85
>-2*2*((3/(-4)+0.5))-(((-5)*2-3)/7)2.85714
>1/(1+(1/(2+(1/(3+(1/4))))))0.697674
>2.5*((6-(3/2))*(6-(3/2)))/1.25-(5*5-(4*3))/(2*-1)47
>
手动分割线：
step101:C:\Users\wangrusheng\CLionProjects\untitled28\main.cpp
#include <iostream>
#include <string>
#include <map>
#include <regex>
#include <cctype>
#include <vector>
#include <algorithm>
#include <sstream>
#include <stdexcept>
#include <fstream> // 新增文件流支持using namespace std;map<string, double> variables;// 辅助函数：跳过空白字符
void skip_whitespace(const string& expr, size_t& pos) {while (pos < expr.size() && isspace(expr[pos])) pos++;
}// 表达式解析函数声明
double eval_expression(const string& expr, size_t& pos);
double eval_term(const string& expr, size_t& pos);
double eval_factor(const string& expr, size_t& pos);
double eval_primary(const string& expr, size_t& pos);// 主解析函数
double evaluate(const string& expr) {size_t pos = 0;double result = eval_expression(expr, pos);skip_whitespace(expr, pos);if (pos != expr.size()) {throw runtime_error("Unexpected characters in expression");}return result;
}// 表达式解析实现
double eval_expression(const string& expr, size_t& pos) {return eval_term(expr, pos);
}double eval_term(const string& expr, size_t& pos) {double left = eval_factor(expr, pos);skip_whitespace(expr, pos);while (pos < expr.size()) {char op = expr[pos];if (op != '+' && op != '-') break;pos++;double right = eval_factor(expr, pos);if (op == '+') left += right;else left -= right;skip_whitespace(expr, pos);}return left;
}double eval_factor(const string& expr, size_t& pos) {double left = eval_primary(expr, pos);skip_whitespace(expr, pos);while (pos < expr.size()) {char op = expr[pos];if (op != '*' && op != '/') break;pos++;double right = eval_primary(expr, pos);if (op == '*') left *= right;else {if (right == 0) throw runtime_error("Division by zero");left /= right;}skip_whitespace(expr, pos);}return left;
}double eval_primary(const string& expr, size_t& pos) {skip_whitespace(expr, pos);if (pos >= expr.size()) {throw runtime_error("Unexpected end of expression");}if (expr[pos] == '(') {pos++;double value = eval_expression(expr, pos);skip_whitespace(expr, pos);if (pos >= expr.size() || expr[pos] != ')') {throw runtime_error("Missing closing parenthesis");}pos++;return value;}if (expr[pos] == '+' || expr[pos] == '-') {bool negative = (expr[pos] == '-');pos++;double value = eval_primary(expr, pos);return negative ? -value : value;}if (isdigit(expr[pos]) || expr[pos] == '.') {size_t start = pos;bool has_decimal = false;while (pos < expr.size() && (isdigit(expr[pos]) || expr[pos] == '.')) {if (expr[pos] == '.') {if (has_decimal) throw runtime_error("Invalid number format");has_decimal = true;}pos++;}return stod(expr.substr(start, pos - start));}throw runtime_error("Unexpected character: " + string(1, expr[pos]));
}// 变量替换函数
string replace_variables(const string& expr) {regex var_re(R"(\b([a-zA-Z_]\w*)\b)");smatch match;string result;size_t last = 0;auto begin = expr.cbegin();while (regex_search(begin, expr.cend(), match, var_re)) {result += string(begin, begin + match.position());string var = match[1];if (!variables.count(var)) {throw runtime_error("Undefined variable: " + var);}result += to_string(variables[var]);begin += match.position() + match.length();last = begin - expr.begin();}result += expr.substr(last);return result;
}// 处理单行输入
void process_line(const string& line) {try {string trimmed = line;trimmed.erase(remove_if(trimmed.begin(), trimmed.end(), ::isspace), trimmed.end());if (trimmed.empty()) return;// 处理赋值语句smatch match;regex assign_re(R"(^([a-zA-Z_]\w*)=(.*)$)");if (regex_match(trimmed, match, assign_re)) {string var = match[1];string expr = replace_variables(match[2]);variables[var] = evaluate(expr);cout << var << " = " << variables[var] << endl;}// 处理普通表达式else {string expr = replace_variables(trimmed);double result = evaluate(expr);cout << result << endl;}} catch (const exception& e) {cerr << "Error: " << e.what() << endl;}
}int main() {// 设置默认文件路径（使用原始字符串避免转义）const string filepath = R"(C:\Users\wangrusheng\CLionProjects\untitled28\cmake-build-debug\input.txt)";// 打开输入文件ifstream input_file(filepath);if (!input_file.is_open()) {cerr << "Error: Could not open input file at:\n" << filepath << endl;return 1;}// 逐行读取并处理string line;while (getline(input_file, line)) {process_line(line);}input_file.close();return 0;
}
step102:C:\Users\wangrusheng\CLionProjects\untitled28\cmake-build-debug\input.txt
3/4*((2-(5/6))/(7/12)+(1/3)*(9/5)-(2/15))
-2*2*((3/(-4)+0.5))-(((-5)*2-3)/7)
1/(1+(1/(2+(1/(3+(1/4))))))2.5*((6-(3/2))*(6-(3/2)))/1.25-(5*5-(4*3))/(2*-1)
step103:运行
C:\Users\wangrusheng\CLionProjects\untitled28\cmake-build-debug\untitled28.exe
1.85
2.85714
0.697674
47Process finished with exit code 0
手动分割线
用python实现
step201:
import reclass Evaluator:def __init__(self):self.variables = {}def skip_whitespace(self, expr, pos):while pos[0] < len(expr) and expr[pos[0]].isspace():pos[0] += 1def eval_expression(self, expr, pos):return self.eval_term(expr, pos)def eval_term(self, expr, pos):left = self.eval_factor(expr, pos)self.skip_whitespace(expr, pos)while pos[0] < len(expr):op = expr[pos[0]]if op not in '+-':breakpos[0] += 1right = self.eval_factor(expr, pos)if op == '+':left += rightelse:left -= rightself.skip_whitespace(expr, pos)return leftdef eval_factor(self, expr, pos):left = self.eval_primary(expr, pos)self.skip_whitespace(expr, pos)while pos[0] < len(expr):op = expr[pos[0]]if op not in '*/':breakpos[0] += 1right = self.eval_primary(expr, pos)if op == '*':left *= rightelse:if right == 0:raise RuntimeError("Division by zero")left /= rightself.skip_whitespace(expr, pos)return leftdef eval_primary(self, expr, pos):self.skip_whitespace(expr, pos)if pos[0] >= len(expr):raise RuntimeError("Unexpected end of expression")if expr[pos[0]] == '(':pos[0] += 1value = self.eval_expression(expr, pos)self.skip_whitespace(expr, pos)if pos[0] >= len(expr) or expr[pos[0]] != ')':raise RuntimeError("Missing closing parenthesis")pos[0] += 1return valueif expr[pos[0]] in '+-':sign = -1 if expr[pos[0]] == '-' else 1pos[0] += 1primary = self.eval_primary(expr, pos)return sign * primaryif expr[pos[0]].isdigit() or expr[pos[0]] == '.':start = pos[0]has_decimal = Falsewhile pos[0] < len(expr) and (expr[pos[0]].isdigit() or expr[pos[0]] == '.'):if expr[pos[0]] == '.':if has_decimal:raise RuntimeError("Invalid number format")has_decimal = Truepos[0] += 1num_str = expr[start:pos[0]]try:return float(num_str)except ValueError:raise RuntimeError(f"Invalid number: {num_str}")raise RuntimeError(f"Unexpected character: {expr[pos[0]]} at position {pos[0]}")def replace_variables(self, expr):def replacer(match):var_name = match.group(1)if var_name not in self.variables:raise RuntimeError(f"Undefined variable: {var_name}")return str(self.variables[var_name])try:replaced_expr = re.sub(r'\b([a-zA-Z_]\w*)\b', replacer, expr)except RuntimeError as e:raise ereturn replaced_exprdef process_line(self, line):stripped = line.replace(' ', '')if not stripped:returntry:match = re.fullmatch(r'^([a-zA-Z_]\w*)=(.*)$', stripped)if match:var = match.group(1)expr = match.group(2)replaced_expr = self.replace_variables(expr)pos = [0]value = self.eval_expression(replaced_expr, pos)if pos[0] != len(replaced_expr):raise RuntimeError(f"Unexpected characters in expression: {replaced_expr[pos[0]:]}")self.variables[var] = valueprint(f"{var} = {value}")else:replaced_expr = self.replace_variables(stripped)pos = [0]value = self.eval_expression(replaced_expr, pos)if pos[0] != len(replaced_expr):raise RuntimeError(f"Unexpected characters in expression: {replaced_expr[pos[0]:]}")print(value)except Exception as e:print(f"Error: {e}")def main():evaluator = Evaluator()filepath = r'C:\Users\wangrusheng\CLionProjects\untitled28\cmake-build-debug\input.txt'try:with open(filepath, 'r') as f:for line in f:evaluator.process_line(line.strip())except IOError as e:print(f"Error opening file: {e}")if __name__ == '__main__':main()
step202:运行
(.venv) PS C:\Users\wangrusheng\PycharmProjects\FastAPIProject1> python hello.py
1.8499999999999996
2.857142857142857
0.6976744186046512
47.0
a = 5.0
b = -7.0
c = -2.0
(.venv) PS C:\Users\wangrusheng\PycharmProjects\FastAPIProject1> end
