95 lines
2.7 KiB
C++
Executable File
95 lines
2.7 KiB
C++
Executable File
#include <memory>
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#include <string>
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#include <iostream>
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using namespace std;
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class MyExpression {
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public:
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virtual int Calculate() const = 0;
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virtual string InLine() const = 0;
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virtual ~MyExpression() {}
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};
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using MyExpressionPtr = shared_ptr<MyExpression>;
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class MyConstClass : public MyExpression {
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public:
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int value;
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MyConstClass(int value);
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int Calculate() const override;
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string InLine() const override;
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};
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class MySumClass : public MyExpression {
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public:
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MyExpressionPtr leftValue;
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MyExpressionPtr rightValue;
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MySumClass(MyExpressionPtr _leftValue, MyExpressionPtr _rightValue);
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int Calculate() const override;
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string InLine() const override;
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};
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class MyProductClass : public MyExpression {
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public:
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MyExpressionPtr leftValue;
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MyExpressionPtr rightValue;
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MyProductClass(MyExpressionPtr _leftValue, MyExpressionPtr _rightValue);
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int Calculate() const override;
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string InLine() const override;
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};
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MyConstClass::MyConstClass(int _value) : value(_value) {}
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int MyConstClass::Calculate() const { return value; }
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string MyConstClass::InLine() const { return to_string(value); }
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MySumClass::MySumClass(MyExpressionPtr _leftValue, MyExpressionPtr _rightValue) :
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leftValue(move(_leftValue)), rightValue(move(_rightValue)) {}
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int MySumClass::Calculate() const { return leftValue->Calculate() + rightValue->Calculate(); }
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string MySumClass::InLine() const { return leftValue->InLine() + " + " + rightValue->InLine(); }
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MyProductClass::MyProductClass(MyExpressionPtr _leftValue, MyExpressionPtr _rightValue) :
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leftValue(move(_leftValue)), rightValue(move(_rightValue)) {}
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int MyProductClass::Calculate() const { return leftValue->Calculate() * rightValue->Calculate(); }
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string MyProductClass::InLine() const {
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string right = rightValue->InLine();
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if (dynamic_cast<MySumClass*>(rightValue.get())) {
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right = "(" + rightValue->InLine() + ")";
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}
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return leftValue->InLine() + " * " + right;
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}
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MyExpressionPtr MyConst(int value) {
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return make_shared<MyConstClass>(value);
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}
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MyExpressionPtr MyProduct(MyExpressionPtr left, MyExpressionPtr right) {
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return make_shared<MyProductClass>(move(left), move(right));
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}
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MyExpressionPtr MySum(MyExpressionPtr left, MyExpressionPtr right) {
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return make_shared<MySumClass>(move(left), move(right));
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}
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int main() {
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MyExpressionPtr myEx1 = MySum(MyProduct(MyConst(3), MyConst(4)), MyConst(5));
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cout << myEx1->InLine() << "\n"; // 3 * 4 + 5
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cout << myEx1->Calculate() << "\n"; // 17
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MyExpressionPtr myEx2 = MyProduct(MyConst(6), myEx1);
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cout << myEx2->InLine() << "\n"; // 6 * (3 * 4 + 5)
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cout << myEx2->Calculate() << "\n"; // 102
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}
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