C++ 实现简易类 Python 解释器 - 支持变量定义、输入输出

#include #include #include #include

using namespace std;

// 定义变量类型 enum VarType { INTEGER, FLOAT, STRING, BOOLEAN };

// 变量类 class Variable { private: VarType type; string value; public: Variable(VarType t, string v) : type(t), value(v) {}

// 获取变量类型
VarType getType() const {
    return type;
}

// 获取变量值
string getValue() const {
    return value;
}

};

// 解释器类 class Interpreter { private: map<string, Variable> variables;

// 将字符串转换为变量类型
VarType getType(const string& typeStr) {
    if (typeStr == "int")
        return INTEGER;
    else if (typeStr == "float")
        return FLOAT;
    else if (typeStr == "str")
        return STRING;
    else if (typeStr == "bool")
        return BOOLEAN;
    else
        return STRING;  // 默认为字符串类型
}

public: // 执行源代码 void execute(const string& code) { istringstream iss(code); string line;

    while (getline(iss, line)) {
        processLine(line);
    }
}

private: // 处理每行代码 void processLine(const string& line) { istringstream iss(line); string token; iss >> token;

    if (token == "print") {
        // 输出变量值
        string varName;
        iss >> varName;
        printVariable(varName);
    } else if (token == "input") {
        // 输入变量值
        string varName;
        iss >> varName;
        inputVariable(varName);
    } else if (token == "var") {
        // 定义变量
        string varName;
        string varType;
        string varValue;
        iss >> varName >> varType >> varValue;
        defineVariable(varName, varType, varValue);
    } else {
        cout << "Invalid statement: " << line << endl;
    }
}

// 输出变量值
void printVariable(const string& varName) {
    if (variables.count(varName) == 0) {
        cout << "Variable not found: " << varName << endl;
        return;
    }
    
    Variable var = variables[varName];
    cout << var.getValue() << endl;
}

// 输入变量值
void inputVariable(const string& varName) {
    if (variables.count(varName) == 0) {
        cout << "Variable not found: " << varName << endl;
        return;
    }
    
    Variable var = variables[varName];
    string input;
    cin >> input;
    
    // 检查输入类型和变量类型是否匹配
    if (var.getType() == INTEGER && !isInteger(input)) {
        cout << "Invalid input type, expected integer" << endl;
        return;
    } else if (var.getType() == FLOAT && !isFloat(input)) {
        cout << "Invalid input type, expected float" << endl;
        return;
    } else if (var.getType() == BOOLEAN && !isBoolean(input)) {
        cout << "Invalid input type, expected boolean" << endl;
        return;
    }
    
    variables[varName] = Variable(var.getType(), input);
}

// 定义变量
void defineVariable(const string& varName, const string& varType, const string& varValue) {
    VarType type = getType(varType);
    variables[varName] = Variable(type, varValue);
}

// 检查是否为整数
bool isInteger(const string& str) {
    if (str.empty())
        return false;
    
    for (char c : str) {
        if (!isdigit(c))
            return false;
    }
    
    return true;
}

// 检查是否为浮点数
bool isFloat(const string& str) {
    if (str.empty())
        return false;
    
    bool decimalFound = false;
    for (char c : str) {
        if (c == '.') {
            if (decimalFound)
                return false;
            decimalFound = true;
        } else if (!isdigit(c)) {
            return false;
        }
    }
    
    return true;
}

// 检查是否为布尔值
bool isBoolean(const string& str) {
    return (str == "True" || str == "False");
}

};

int main() { // 创建解释器实例 Interpreter interpreter;

// 执行源文件
interpreter.execute(
    "var name str \"John\"

" "var age int 20 " "var height float 1.75 " "var is_student bool True " "print name " "print age " "print height " "print is_student " "input name " "input age " "input height " "input is_student " "print name " "print age " "print height " "print is_student " );

return 0;

}