切换语句的奇怪行为c ++

Question

过去3个小时我一直在看这段代码而且我很困惑.我感谢任何帮助,谢谢.

file:UnsortedType.h

#include "ItemType.h"
class UnsortedType{

public:
    UnsortedType();
    void RetireveItem(ItemType& item, bool& found);
    bool InsertItem(ItemType item);
private:
    int length;
    ItemType info[MAX_ITEMS];
};

file:UnsortedType.cpp

#include "UnsortedType.h"
#include <iostream>

UnsortedType::UnsortedType() {
    length = 0;
}

void UnsortedType::RetireveItem(ItemType& item, bool& found) {

    bool moreToSearch = true;
    int location = 0;
    found = false;

    moreToSearch = (location < length);

    while (moreToSearch && !found) {

        switch (item.ComparedTo(info[location])) {
            case LESS:
                location++;
                moreToSearch = (location < length);
                break;
            case GREATER:
                location++;
                moreToSearch = (location < length);
                break;
            case EQUAL:
                found = true;
                break;
        }
    }

    if (found) {
        item = info[location];
        std::cout << "Item " << item.getValue() << " has been retrieved." << std::endl;
    }

    else {
        std::cout << "Item " << item.getValue() << " has NOT found and has NOT been retrieved."
    }
}

bool UnsortedType::InsertItem(ItemType item) {

    if (length == MAX_ITEMS) {
        std::cout << "List is Full!" << std::endl;
        std::cout << "Item " << item.getValue() << " has not been added." << std::endl;
        return false;
    } else {
        std::cout << "Item " << item.getValue() << " added successfully." << std::endl;
        info[length] = item;
        length++;
        return true;
    }
}

file:ItemType.h

const int MAX_ITEMS = 40;
enum RelationType{LESS,GREATER,EQUAL};

class ItemType{

private:
    int value;

public:
    ItemType();
    ItemType(int value);
    RelationType ComparedTo(ItemType otherItem);
    void Initialize(int value);
    void printItem();
    int getValue();
};

file:ItemType.cpp

ItemType::ItemType(){
    this->value=0;    
}

ItemType::ItemType(int value){
    this->value = value;
}

RelationType ItemType::ComparedTo(ItemType otherItem){

    if(value < otherItem.value){
        return LESS;
    }

    if(value == otherItem.value){
        return EQUAL;
    }

    if(value < otherItem.value){
        return GREATER;
    }    

}

void ItemType::Initialize(int value){
    this->value = value;
}

void ItemType::printItem(){
    std::cout << "Item Type: " << this->value <<std::endl;
}

int ItemType::getValue(){
    return this->value;
}

请注意:在上面的代码中,我已经省略了一些我认为不相关的代码部分.因此,如果您复制/粘贴代码并运行它可能需要一些包含语句(如iostream)等等.

现在问题是:

当我像这样运行主要:

UnsortedType unsortedType;

bool item3found = false;
ItemType item3(3);
unsortedType.InsertItem(item3);
unsortedType.RetireveItem(item3, item3found);

bool item1found = false;
ItemType item1(1);
unsortedType.InsertItem(item1);
unsortedType.RetireveItem(item1, item1found);

bool item2found = false;
ItemType item2(2);
unsortedType.RetireveItem(item2, item2found);

没有问题.

输出是:

Item 3 added successfully.
Item 3 has been retrieved.
Item 1 added successfully.
Item 1 has been retrieved.
Item 2 has NOT found and has NOT been retrieved.

但是,如果我首先添加item1并检索item1,然后添加item3并检索item3,则switch语句突然停止工作.

所以这是奇怪的情况下的主要文件:

UnsortedType unsortedType;

bool item1found = false;
ItemType item1(1);
unsortedType.InsertItem(item1);
unsortedType.RetireveItem(item1, item1found);

bool item3found = false;
ItemType item3(3);
unsortedType.InsertItem(item3);
unsortedType.RetireveItem(item3, item3found);

bool item2found = false;
ItemType item2(2);
unsortedType.RetireveItem(item2, item2found);

在调试程序的过程中,我一直在寻找:while(moreToSearch &&!found),代码不会转到任何switch语句.任何的想法？

这是奇怪情况下的输出:

Item 1 added successfully.
Item 1 has been retrieved.
Item 3 added successfully.

RUN FAILED (exit value 1, total time: 1s)

任何帮助大大挪用,我即将失去它!

Answer 1

问题似乎在您的ComparedTo成员函数中:

RelationType ItemType::ComparedTo(ItemType otherItem){

    if(value < otherItem.value){
        return LESS;
    }

    if(value == otherItem.value){
        return EQUAL;
    }

    if(value < otherItem.value){
        return GREATER;
    }    

}

GREATER案件的比较似乎不正确.对于这样的功能,它将使意义,你不允许通过它的可能路径,将不返回值(即,使用if,else if,else).此外,您可能希望打开所有编译器警告并将其视为错误; 这将有助于避免这样的问题.