动态布尔数组构造函数问题

Question

I'm having problems with the constructor of a class with an array of booleans, representing whether a int value is present by holding a "true" value at that index. So if I create a new set:

IntSet set(4, 5, 6); // up to 5 parameters may be entered, with default values if some are missing.

this will create an array of size 6 (the highest value passed) and the value at indexes 4, 5 and 6 will be set to true, while the rest false.

This is what I have so far but I can't seem to get it to work properly:

.h:

class IntSet {

public:

bool* value;
int size;

// CONSTRUCTORS
IntSet(int val1 = -1, int val2 = -1, int val3 = -1, int val4 = -1, int val5 = -1);
IntSet(const IntSet &other);
~IntSet();

.cpp:

IntSet::IntSet(int val1, int val2, int val3, int val4, int val5) {



// check if all values are default.
if((val1 == -1) && (val2 == -1) && (val3 == -1) && (val4 == -1) && (val5 == -1)) {

    val1 = 1;
    size = 1;

// else if one or more values are not default, find largest value and 
// set size to the value.
} else {

    if(val1 >= val2 && val1 >= val3 && val1 >= val4 && val1 >= val5) {
        size = val1;
    }

    if(val2 >= val1 && val2 >= val3 && val2 >= val4 && val2 >= val5) {
        size = val2;
    }

    if(val3 >= val1 && val3 >= val2 && val3 >= val4 && val3 >= val5) {
        size = val3;
    }

    if(val4 >= val1 && val4 >= val2 && val4 >= val3 && val4 >= val5) {
        size = val4;
    }

    if(val5 >= val1 && val5 >= val2 && val5 >= val3 && val5 >= val4) {
        size = val5;
    }
}

// Create pointer to boolean array of size "size"
value = new bool[size];

// set all values at their specified index to true.
if(val1 >= 0)
    value[val1] = true;

if(val2 >= 0)
    value[val2] = true;

if(val3 >= 0)
    value[val3] = true;

if(val4 >= 0)
    value[val4] = true;

if(val5 >= 0)
    value[val5] = true;
}

//------------------------------------------------------------------------------

IntSet::IntSet(const IntSet &otherSet) : size(otherSet.size){
cout << "In Copy Constructor" << endl;

value = new bool[size];
for(int i = 0; i < size; i++)
    value[i] = otherSet.value[i];
}

//------------------------------------------------------------------------------

IntSet::~IntSet() {
cout << "In Destructor" << endl;

delete[] value;
}

For some reason, when I debug and follow the values, I see "value" set to true(205). I checked by outputting the boolean values in the console and all values print as "205" instead of "0" or "1". I'm not sure what is going on, but I think the issue is with bool *value = new bool[size]; although I've tried many different things and nothing seems to work. I will tackle the copy constructor and destructor once I figure this out.

This is a class assignment, so I'm not looking to get the solution from anyone, but any tips that may point me in the right direction are much appreciated!

Thanks everyone!

Answer 1

In the constructor:

IntSet::IntSet(int val1, int val2, int val3, int val4, int val5);

You create a local variable called the same as the class variable "value", which hides the class declaration.

// Create pointer to boolean array of size "size"
bool *value = new bool[size];

Therefore, the class variable is still unitialized.

Results:

• local variable value causes memory leak
• class variable never defined, will be improperly deleted - runtime error

Instead use:

value = new bool[size];

or

this->value = new bool[size];