41 lines
835 B
C++
41 lines
835 B
C++
/**
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* @name 解释器模式
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* @brief: 定义语言的语法表示
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* @note 场景：SQL解析、正则表达式、数学公式计算
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*/
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class Expression {
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public:
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virtual int interpret() = 0;
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};
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class Number : public Expression {
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public:
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Number(int value) : value(value) {}
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int interpret() override { return value; }
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private:
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int value;
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};
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class Add : public Expression {
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public:
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Add(Expression* left, Expression* right)
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: left(left), right(right) {}
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int interpret() override {
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return left->interpret() + right->interpret();
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}
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private:
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Expression* left;
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Expression* right;
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};
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// 使用：构建表达式树 (2 + (3 + 4))
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Expression* expr = new Add(
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new Number(2),
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new Add(new Number(3), new Number(4))
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);
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int main()
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{
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int result = expr->interpret(); // 输出9
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} |