为什么我在'bool'之前收到此error-：expected primary-expression？

如何解决为什么我在'bool'之前收到此error-：expected primary-expression？

#include<iostream>
#include<string>


using namespace std;
class LFSR
{
private:

    bool lfsr[];
    private: int tap;
    private: int t;
    private: string s;

public: 
    LFSR(string seed,int tap)
    {
        s = seed;
        t = tap;


        lfsr = bool[s.length()];

        t = s.length() - 1 - t;

        for (int i = 0; i < seed.length(); i++)
        {

            if (seed.charAt(i) == 48)
            {

                lfsr[i] = false;
            }
            else
            {

                lfsr[i] = true;
            }
        }
    }
    int step()
    {

        boolean newBit = lfsr[0] ^ lfsr[tap];
        for (int i = 0; i < lfsr.length - 1; i++)
        {

            lfsr[i] = lfsr[i + 1];
        }
        lfsr(lfsr.length - 1) = newBit;
        return newBit == false ? 0 : 1;
    }
    int generate(int k)
    {

        int temp = 0;
        for (int i = 0; i < k; i++)
        {

            temp = 2 * temp;
            temp = temp + step();

        }
        return temp;

    }
};
int main()
{

    LFSR lfsr("01101000010",8);
    for (int i = 0; i < 10; i++)
    {

        int bit = lfsr.step();
        cout << lfsr << "+" << " " << bit;
    }
    LFSR lfsr("0110100010",8);
    cout << "Testing generate()";

    for (int i = 0; i < 10; i++)
    {

        int r = lfsr.generate(5);
        cout << lfsr.to_string() << " " << r;
    }
    return 0;
}

在此行：

      lfsr=bool[s.length()];

我收到上述错误。

我要做什么？

我正在尝试创建大小为10（种子长度或寄存器数量）的LFSR。

我的问题？

我为什么会得到这个错误？

如何解决此错误？

我试图在C ++中执行的Java代码 我会给你代码，让我们看看。

public class LFSR {
 private boolean[] lfsr;
 private int tap;
/**
 * @param args the command line arguments
 */
public static void main(String[] args)
 {
 LFSR lfsr = new LFSR("01101000010",8);
System.out.println("Testing step()");
 for (int i = 0; i < 10; i++)
 {
 int bit = lfsr.step();
System.out.println(lfsr + " " + bit);
}
 lfsr = new LFSR("01101000010",8);
System.out.println("\nTesting generate()");
 for (int i = 0; i < 10; i++)
 {
 int r = lfsr.generate(5);
System.out.println(lfsr + " " + r);
}
 }
 public LFSR(String seed,int tap)
 {
 lfsr = new boolean[seed.length()];
 this.tap = (seed.length()-1)-tap;
 for(int i = 0; i < seed.length(); i++)
 {
 if(seed.charAt(i) == 48)
 {
 lfsr[i] = false;
}
 else
{
 lfsr[i] = true;
}
 }
 }

 public int step()
 {
 boolean newBit = lfsr[0] ^ lfsr[tap];
 for(int i = 0; i < lfsr.length-1; i++)
 {
 lfsr[i] = lfsr[i+1];
}
 lfsr[lfsr.length-1] = newBit;
 return newBit == false ? 0 : 1;
}
 public int generate(int k)
 {
 int temp = 0;
 for(int i = 0; i < k; i++)
 {
 temp *= 2;
temp += step();
}
 return temp;
}
 public String toString()
 {
 String representation = "";
 for(int i = 0; i < lfsr.length; i++)
 {
 representation += lfsr[i] == false ? 0 : 1;
}
 return representation;
}
}

解决方法

不要像Java那样尝试对C ++进行编程，语法不同，语义完全不同。

例如（可能）

#include <vector>
#include <string>

private:
    std::string s;
    int t;
    std::vector<bool> lfsr;

public:
    LFSR(const std::string& seed,int tap) : s(seed),t(tap),lfsr(seed.length())
    {
        ...
    }

,

这是一个可能的解决方案。我认为，您可以将其与Java代码进行比较，并查看差异。

#include <vector>
#include <string>
#include <iostream>

class LFSR {
private:
    std::vector<bool> lfsr;
    int tap;

public:
    LFSR(std::string seed,int tap) {
        lfsr.reserve(seed.length());
        this->tap = (seed.length()-1) - tap;
        for(std::size_t i = 0; i < seed.length(); i++) {
            lfsr.push_back(seed.at(i) == '0');
        }
    }

    int step() {
        bool newBit = lfsr[0] ^ lfsr[tap];
        for(std::size_t i = 0; i < lfsr.size()-1; i++) {
            lfsr[i] = lfsr[i+1];
        }
        lfsr[lfsr.size()-1] = newBit;
        return newBit == false ? 0 : 1;
    }

    int generate(int k) {
        int temp = 0;
        for(int i = 0; i < k; i++) {
            temp *= 2;
            temp += step();
        }
        return temp;
    }

    std::string toString() const {
        std::string  representation = "";
        for(std::size_t i = 0; i < lfsr.size(); i++) {
            representation += lfsr[i] == false ? 0 : 1;
        }
        return representation;
    }

    friend std::ostream& operator<<(std::ostream &stream,LFSR const &lfsr) {
        return stream << lfsr.toString();
    }
};


int main() {
    LFSR lfsr("01101000010",8);
    std::cout << "Testing step()";
    for (int i = 0; i < 10; i++) {
        int bit = lfsr.step();
        std::cout << lfsr << " " << bit;
    }
    LFSR lfsr2("01101000010",8);
    std::cout << "\nTesting generate()";

    for (int i = 0; i < 10; i++) {
        int r = lfsr2.generate(5);
        std::cout << lfsr2 << " " << r;
    }
}

,

您可以将lfsr的声明更改为std::unique_ptr<bool[]> lfsr;。然后：

lfsr=new bool[s.length()];

您不必担心删除数组指针了；它是一个即发即弃的std实用程序，其行为类似于数组，但会降低该类的可复制性。即LFSR将不能分配，也不能复制构造。

另一个选项是std::vector，如先前的答复所述。

PS：不要忘记标题：

#include <memory>

干杯， FM。