帮帮我，写的c++虚拟机为什么一开始需要输入两个数字才开始执行#include <iostream>

Question

为什么一开始需要输入两个数字才开始执行

#include<iostream>
#include<string>
#include<vector>
using namespace std;

class QD_ALU {
public:
    const string& aluName;
    int AC;
    QD_ALU(const string& aluName) :aluName(aluName), AC(0) {}
};

class QD_Memory {
public:
    vector<int> memory;
    QD_Memory(int size) : memory(size, 0) {}
};

class QD_In {
public:
    const string& inName;
    QD_In(const string& inName) :inName(inName) {}
    int read() {
        int input;
        cin >> input;
        return input;
    }
};

class QD_Out {
public:
    const string& outName;
    QD_Out(const string& outName) :outName(outName) {}
    void write(int output) {
        cout << output << std::endl;
    }
};
class QD_CU {
public:
    const string& cuName;
    int PC;
    QD_CU(const string& cuName, QD_Memory* m, QD_In* in, QD_Out* out, QD_ALU* alu) :cuName(cuName), PC(0), m(m), in(in), out(out), alu(alu) {}
    void run(vector<int>& instructions) {
        while (instructions[PC] != 4300) {
            execute(instructions[PC]);
        }
    }
private:
    QD_Memory* m;
    QD_In* in;
    QD_Out* out;
    QD_ALU* alu;
    void execute(int instruction) {
        switch (instruction / 100) {
        case 10:
            m->memory[instruction % 100] = in->read();
            cout << "read: " << in->read() << " adress: " << instruction % 100 << endl;
            PC++;
            
            break;
        case 11:
            cout << "write: " << m->memory[instruction % 100]<<" adress: " << instruction % 100 << endl;
            out->write(m->memory[instruction % 100]);
            PC++;
            break;
        case 20:
            alu->AC = m->memory[instruction % 100];
            cout << "adress:"<< instruction % 100<<" AC "<<alu->AC<<endl;
            PC++; 
            break;
        case 21:// STORE
            m->memory[instruction % 100] = alu->AC;
            PC++; 
            cout << " AC " << alu->AC << "adress:" << instruction % 100 << endl;
            break;
        case 30:// ADD
            alu->AC += m->memory[instruction % 100];
            PC++;
            cout << " AC " << alu->AC << endl;
            break;
        case 31:
            // SUB
            alu->AC -= m->memory[instruction % 100];
            PC++; 
            cout << " AC " << alu->AC << endl;
            break;
        case 40:
            // BR
            PC = instruction % 100;
            cout << PC;
            break;
        default:
            std::cout << "Invalid instruction: " << instruction << std::endl;
            break;
        }
    }
};
class Computer {
public:
    QD_CU cu;
    QD_ALU alu;
    QD_Memory memory;
    QD_In in;
    QD_Out out;
    Computer(const string& cuName, const string& aluName, int memorySize, const string& inName, const string& outName)
        : cu(cuName, &memory, &in, &out, &alu), alu(aluName), memory(memorySize), in(inName), out(outName) {}
    void run(vector<int>& instructions) {
        cu.run(instructions);
    }
};

int main() {
    Computer mycomputer1("青芯CU1", "青芯ALU1", 1024, "输入设备1", "输出设备1");
    vector<int> instructions = { 1007, 1008, 2007, 3008, 2109, 1109, 4010, 0000, 0000, 0000, 4300 };
    mycomputer1.run(instructions);
    return 0;
}

Answer 1

这段代码要求什么？