c++ - 复制赋值构造函数中的语法错误

Question

我一直在为无符号整数开发自己的 Vector 实现，以了解有关如何定义自己的构造函数的更多信息。我也没有使用任何标准库，只是为了了解更多关于如何从头开始制作 vector 的信息。

经过一些研究，我现在已经写了一些我认为应该是正确的构造函数，但我遇到了一些奇怪的错误，我似乎无法弄清楚它们出现的原因。可能是我误解了构造函数的外观？

我将不胜感激您能提供的所有帮助!

这是我认为在定义时导致错误的构造函数:

UIntVector& UIntVector::operator=(UIntVector&& other){
if (this != &other) {
    unsigned int * begin = allocate(sizeof(unsigned int)*other.vsize);
    unsigned int * end = (other.vAddress + (sizeof(unsigned int)*other.vsize));
    copyV(other.vAddress, end, begin);
    deleteV(other.vAddress, end);

    vAddress = begin;
    vsize = other.vsize;

    other.vAddress = nullptr;
    other.vsize = 0;
}
return *this;
}

这些是我在 visual studio 中遇到的错误(上面的构造函数在第 48 行):

uintvector.cpp(48): error C2059: syntax error: 'if'

uintvector.cpp(48): error C2143: syntax error: missing ';' before '{'

uintvector.cpp(48): error C2447: '{': missing function header (old-style formal list?)

uintvector.cpp(60): error C2059: syntax error: 'return'

uintvector.cpp(61): error C2059: syntax error: '}'

uintvector.cpp(61): error C2143: syntax error: missing ';' before '}'

uintvector.cpp(69): error C2143: syntax error: missing ';' before '{'

uintvector.cpp(69): error C2447: '{': missing function header (old-style formal list?)

UintVector.hpp完整代码

#include <iostream>

class UIntVector {
private:
    size_t vsize;
    unsigned int * vAddress;

    // Will allocate memory for the vector
    unsigned int * allocate(size_t size);
    // Will copy the range of the 
    void copyV(unsigned int * begin, unsigned int * end, unsigned int * dest);
    // Will delete reserved memory.
    void deleteV(unsigned int * begin, unsigned int * end);

    void reset(void);
    std::size_t size() const;
    unsigned int * getAddress();

public:

    // If UIntVector is called without parameter it should have 0 elements.
    UIntVector();

    // A constructor that just takes a single argument and then we create a vector with 7 containers.
    UIntVector(std::size_t length);

    // A copy constuctor.
    // Probably have to be explicit due to otherwise converting, don't know though
    UIntVector(const UIntVector& original);

    // Should be a deconstructor.
    ~UIntVector();

    // Should be a move constructor
    UIntVector(UIntVector&& other);

    // initializer_list
    UIntVector(std::initializer_list<int> list);

    // a copy-assignment, and a move-assignment, operator taking another UIntVector (potentially of a different size), and;
    UIntVector& operator=(UIntVector& other);

    /*
    – overloads of operator[] that makes it possible to access/modify elements at a desired index.
        ? The first element of the container shall be at index 0.
        ? An exception of type std::out_of_range shall be thrown if a user tries
            to access an index out-of-bounds
    */
    unsigned int& operator[](size_t index) const;
};

UIntVector.cpp完整代码:

#include <iostream>
#include "UIntVector.hpp" 

// If UIntVector is called without parameter it should have 0 elements.
UIntVector::UIntVector() {
    vAddress = allocate(0);
    vsize = 0;
    // should create just an empty vector
}

// A constructor that just takes a single argument and then we create a vector with 7 containers.
UIntVector :: UIntVector(std::size_t length) {
    // should take length and create a vector with 7 containers.
    vAddress = allocate(length);
    vsize = length;
}

// A copy constuctor.
// Probably have to be explicit due to otherwise converting, don't know though
UIntVector::UIntVector(const UIntVector& original) {
    std::size_t originalsize = original.size();
    vAddress = allocate(originalsize);
    vsize = originalsize;
    unsigned int a = originalsize*(sizeof(unsigned int));
    unsigned int * end = original.vAddress + a;
    copyV(original.vAddress, end, vAddress);
}
// Should be a deconstructor
UIntVector::~UIntVector() {
    deleteV(vAddress, vAddress + (sizeof(unsigned int)*vsize));
}

// Should be a move constructor
UIntVector::UIntVector(UIntVector&& other) {
    vAddress = other.getAddress();
    vsize = other.size();
    other.vsize = 0;
    other.vAddress = nullptr;
}

// Should be a constructor with initializer_list
UIntVector::UIntVector(std::initializer_list<int> list) {
    // std::initializer_list
}


// a copy-assignment, and a move-assignment, operator taking another UIntVector (potentially of a different size), and;
UIntVector& UIntVector::operator=(UIntVector& other){
    if (this != &other) {
        unsigned int * begin = allocate(sizeof(unsigned int)*other.vsize);
        unsigned int * end = (other.vAddress + (sizeof(unsigned int)*other.vsize));
        copyV(other.vAddress, end, begin);
        deleteV(other.vAddress, end);

        vAddress = begin;
        vsize = other.vsize;

        other.vAddress = nullptr;
        other.vsize = 0;
    }
    return *this;
}


/*
– overloads of operator[] that makes it possible to access/modify elements at a desired index.
? The first element of the container shall be at index 0.
? An exception of type std::out_of_range shall be thrown if a user tries
to access an index out-of-bounds
*/
unsigned int& UIntVector::operator[](size_t index) const {
    try {
        unsigned int * indexadress = vAddress + (sizeof(unsigned int)*index);
        return *indexadress;
    }
    catch (std::out_of_range& e) {
        std::cout << "Out of range: " << e.what() << "\n";
    }
    catch (std::exception& e) {
        std::cout << "Some other exception: " << e.what() << "\n";
    }
}


// Will allocate memory for the vector
unsigned int * UIntVector :: allocate(size_t size) {
    vsize = size;
    return (unsigned int *)malloc(sizeof(unsigned int) * size);
}

// Will copy the range of the 
void UIntVector :: copyV(unsigned int * begin, unsigned int * end, unsigned int * dest) {
    while (begin != end){
        *dest = *begin;
        begin += sizeof(unsigned int);
        dest += sizeof(unsigned int);
    }
}

void UIntVector :: deleteV(unsigned int * begin, unsigned int * end) {
    while (begin != end){
        free(begin);
        begin += sizeof(unsigned int);
    }
}

void UIntVector::reset(void) {

    unsigned int * address = getAddress();
    unsigned int a = {};
    for (int i = 0; i < size(); i++) {
        *address = a;
        address += sizeof(unsigned int);
    }

}

std::size_t UIntVector :: size(void) const {
    return vsize;
}

unsigned int * UIntVector::getAddress(void){
    return vAddress;
}

Answer 1

原来是visual studio版本问题，我下载的是visual studio 2013而不是最新的Mircosoft Visual Studio Community 2015。

我猜这是由于新标准，这个程序是为 c++11 编写的，因此我得到了错误。非常感谢大家提供的测试帮助。